By Team Dirty
Feb 25, 2023,
Casseroles are humble heroes of homestyle cooking. Not many comfort food dishes are as versatile or equally at ease on a formal holiday table as they are on a TV tray stand. Dressed up or dressed down, casseroles are delicious, and our Dairy-Free Vegetable Gratin is no exception.
Mixed veggies are lightly sautéed and folded into a creamy cashew sauce before everything is topped with homemade seasoned breadcrumbs and baked to toasty perfection. We even include instructions on preparing everything ahead of time, so all you have to do is throw the casserole in the oven. You’ll love this simply elegant crowd-pleaser.
Seasoned breadcrumb topping
Bread slices: it’s super easy to make your own breadcrumbs—all you need is bread (a little stale is best) and a food processor. We recommend 100% whole grain, sprouted, or gluten-free bread, but whatever you use is fine. Just check to ensure it’s free from oil and refined sugar.
Nutritional yeast: (AKA nooch) a non-active yeast that’s slightly cheesy-tasting and great for flavoring many plant based dishes and sauces. It’s nice and savory, which makes the breadcrumbs super yummy.
Mushrooms, carrots, bell peppers, onions: these readily available vegetables create a nice contrast in texture and flavor, but they’re super flexible so feel free to substitute. If you do want to swap any out, try to stick to veggies that are similar in firmness (i.e. soft veggies for the mushrooms, firm veggies for the carrots, etc). For the onion, substituting with another allium (leeks, shallots, or other variety of onion) will yield the best results.
Frozen peas and corn: using the frozen varieties of these delicate veggies offers the best texture and sweet flavor. If you’d like to substitute with canned or fresh, feel free. You’ll want to add fresh corn kernels to the pan and sauté along with the other fresh veggies. Fresh peas or drained canned varieties can be added when the frozen veggies would be.
Cashews: the uses for cashews are endless. Soaking and processing them in the blender with a few other ingredients produces a silky, creamy, and rich sauce that hugs and complements the sautéed veggies perfectly.
Non-dairy milk: any variety will work, just be sure it’s unsweetened and unflavored. We like soy, almond, or oat milk for this recipe. We can show you how to milk an almond if you need to cross that off the ol’ bucket list!
Canned navy beans: using beans in sauces adds nutrition and fiber without adding lots of fat. They contribute to the creaminess, although the texture isn’t as fine as cashews. Substituting part or all of the nuts in a plant based sauce with beans is especially useful for people with diabetes or other blood sugar issues.
Garlic cloves: using whole uncooked garlic cloves in a sauce may seem intense, but don’t fret. The oven will cook off the strong raw garlic flavors and leave our sauce with deep, roasted notes you’ll love.
Let’s make our Dairy-Free Vegetable Gratin
If you plan on baking and eating your casserole immediately, preheat your oven to 400ºF (205ºC). You’ll need a 2-quart 8x8x2-inch baking dish or a 9-inch pie plate.
Soak your cashews and prep your veggies before starting so everything comes together smoothly.
From bread to crumbs
Take your bread (you’ll want about one slice for every ½ cup of breadcrumbs called for) and tear into large, uniform pieces. Toss those into your food processor and pulse until you have a uniform cumb texture. How coarse or fine you process is up to you. Read all about how to make your own breadcrumbs.
Measure out what you need and transfer your breadcrumbs to a separate bowl. Add the rest of your topping ingredients and stir with a fork or whisk to combine.
Set aside for now. If you plan to bake and serve your casserole another day, store the breadcrumb topping in an airtight container on the counter or in the fridge.
Grab a large-ish skillet and warm over medium heat until hot. Add the mushrooms, carrots, bell peppers, and onions and sauté, stirring occasionally, until just tender but not completely soft, about 10 minutes. If things start to stick, add a splash of water and stir.
Add the frozen peas and corn along with the fresh parsley. Stir until everything is combined and heated through, about two minutes. If the peas and corn are still cold in spots, that’s fine. They’ll be thoroughly cooked in the oven.
Remove your veggies from the heat and transfer to a large mixing bowl.
Blend baby blend
Drain your soaked cashews and discard the water. If you have a high-powered blender, you can skip the soaking step altogether. #Fancy. If you’re on the search for a new blender, we suggest reading The 411 on Blenders to Help You Pick Which One is Best for You.
Put the cashews into your blender along with the non-dairy milk, navy beans, nutritional yeast, garlic, lemon juice, salt, pepper, and thyme.
Blend until completely smooth and creamy. If things are too thick and not blending well, you can add a splash of non-dairy milk and stir (with the blender off), but be careful not to add too much. You want your sauce thick enough to coat the veggies and deliver that casserole creaminess you expect.
Speaking of sauce, we truly believe the sauce IS the boss! As a member of Plant Fueled Life, you’ll have access to these creamy, dreamy plant based & dairy-free sauces. They’re loved by vegans, flexitarians, and judgy co-workers alike!
Mix it up
Pour your sauce over the sautéd veggies and stir until well combined. (Don’t forget to lick the spoon!)
Transfer your veggie/sauce mixture to your baking dish and spread it out in an even layer. If you’re preparing your casserole to bake later, let it cool to room temperature before covering and storing it in the fridge for up to five days. Otherwise, move on to the next step.
Bake and serve
Sprinkle the breadcrumb topping evenly over your casserole and bake in your preheated oven (uncovered) until hot and the breadcrumbs are toasted, about 15–25 minutes. If the edges of your breadcrumbs start to brown and burn before the center crumbs, you can use a few strips of aluminum foil folded over the edges of the pan to protect the crumbs there. Just be sure not to cover the center of the casserole.
Once the timer beeps and things look golden and delicious, remove your Dairy-Free Vegetable Gratin from the oven and let rest for about 10 minutes before serving. Then dish that baby up and enjoy!
If you’re preparing and baking on different days, pull your refrigerated casserole and breadcrumbs (if applicable) out of the fridge when you’re ready and let them sit on the counter while you preheat your oven to 400ºF (205ºC).
Giving cold foods some time to warm up before sticking them in a hot oven promotes more even and faster cooking. Just be careful not to leave perishable items out for an extended amount of time.
Once your oven is hot, sprinkle the breadcrumbs over your casserole in an even layer and bake (uncovered) until hot and the breadcrumbs are toasted, about 20–30 minutes. Remove from the oven and give your gratin about 10 minutes to rest before serving.
Store any leftovers in an airtight container in the fridge for up to five days (if you waited several days between prepping and baking the casserole, you may want to limit leftover storage to two or three days).
- 1 2-quart 8x8x2-inch baking dish or a 9-inch pie plate
Seasoned breadcrumb topping
- ½ cup breadcrumbs, directions below (35 g / we prefer 100% whole grain, sprouted, or gluten-free bread / 1 slice typically makes about ½ cup crumbs)
- 1 tablespoon nutritional yeast (5 g)
- ¼ teaspoon dried thyme
- ¼ teaspoon garlic powder
- 2 cups mushrooms, diced (140 g / any variety)
- 1 cup carrots, diced (130 g)
- 1 cup red bell pepper, diced (150 g)
- ½ cup yellow onion, diced (80 g)
- 1 cup frozen peas (135 g)
- 1 cup frozen corn kernels (135 g)
- ¼ cup parsley, chopped (5 g / any variety)
- 1 cup raw cashews, soaked in water for 10 minutes (130 g)
- ¾ cup non-dairy milk (177 ml / unsweetened and unflavored)
- ½ cup canned navy beans, drained and rinsed (75 g)
- 3 tablespoons nutritional yeast (15 g)
- 1 tablespoon garlic cloves, peeled and left whole (10 g / about 3-4 cloves)
- 1 tablespoon lemon juice
- ¾ teaspoon salt
- ½ teaspoon fresh black pepper (about 20 turns)
- ½ teaspoon dried thyme
- Preheat your oven to 400°F (205°C). Tear your bread into large uniform pieces then place them into your food processor. Process until you have uniform breadcrumbs (about 20 seconds).
- Measure what you need for this recipe then transfer to a bowl and add the rest of the topping ingredients. Stir to combine then set aside.
- Heat a large skillet over medium heat until warm, about 2 minutes. Add the mushrooms, carrot, bell pepper, and onion. Sauté until tender, about 10 minutes.
- Add the frozen peas, frozen corn, and parsley. Stir until everything is combined and heated through, about 2 minutes. Remove from the heat and transfer to a larege mixing bowl.
- Make the sauce while your veggies are sautéing. Drain the cashews (discard the soaking water) and place them into your blender, along with all of the sauce ingredients. Blend until smooth and creamy.
- Add the blender mixture to the bowl with the sautéed vegetables and stir until everything is combined. Transfer to your baking dish and spread out in an even layer.
- Sprinkle the breadcrumb topping evenly over the top of the casserole. Bake (uncovered) until hot all the way through and the breadcrumbs are toasted, 15–25 minutes.
- Remove from the oven and allow to rest for 10 minutes. Enjoy!
How to serve
This Dairy-Free Vegetable Gratin is scrumptious on its own, but it pairs particularly well with these:
- Steamed veggies or a side salad with oil-free dressing
- These tangy Lemon-Tarragon Root Veggies
- A refreshing Tomato Mint Salad
- Zesty Broccoli from Plant Fueled Life
What’s your favorite way to dress casseroles up (or down)? Have you made our Diary-Free Vegetable Gratin? Tell us all about it in the comments below.
Here’s to celebration-worthy comfort food that’s good for you, too!
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This recipe is one of my all-time favorites. Easy to make and the whole family loves it.
I also love this recipe and I’m happy to see that it’s been lightened up with navy beans for the sauce. It was so delicious, however really rich in the original version. Will definitely be making this again very soon!