Place the brown rice, lentils, oats and barley in a fine mesh strainer and rinse well with water. Tap the strainer against the sink to remove as much excess water as possible.
Press the saute setting on your Instant Pot and heat up the inner pot for 2 minutes. Transfer the rinsed grain mixture along with the cinnamon stick to the Instant Pot and saute for 2 minutes, stirring frequently.
Turn off the Instant Pot and add the water. Stir, and then lock the lid into place, making sure the nozzle is in the sealing position.
Use the Manual (or Pressure Cooking) mode and set the timer for 12 minutes. Use the natural release method when the timer goes off.
Remove the lid and add the vanilla. Cool to room temperature, then promptly store in your fridge. You can leave the cinnamon stick in for added flavor or take it out before storing.
Once you have your grains made, heat up however much you want in a saucepan with some non-dairy milk. Place in a bowl and top with chopped nuts, fruit, non-dairy milk and a little sweetener of your choice.
Notes
We haven't tested it, but you can make this on the stove top by using 3 or 4 cups of water (same amount of grains / lentils) and simmering it for about 30-35 minutes until the rice and lentils are soft. You might start with 3 cups of water and add more if necessary.
You can make this gluten free by using toasted buckwheat instead of barley and follow the same instructions. You could also use 1/8 cup more rice and 1/8 cup more oats and leave out the barley.