Heat a large pot and sauté the onions for 5 minutes, stirring frequently and adding a splash of water when they start to stick to the pan.
Add the bell pepper, celery, tempeh, garlic, and dried basil, and cook for an additional 5 minutes, stirring intermittently and adding just a splash of water when the ingredients start to stick to the bottom of the pan.
While the veggie / tempeh mixture is cooking, drain the dates from the water (be sure the pit is taken out) and place them in the blender along with the soy sauce, water and apple cider vinegar, and blend until totally smooth, about 1 minute.
Pour the date mixture and the tomato sauce in the veggie / tempeh mixture and stir.
Simmer on low, uncovered for 35-40 minutes stirring frequently. The longer it cooks, the thicker it will become. You want the consistency to be nice and thick, not soupy.
Add salt and pepper to taste.
When you turn off the heat, add in the parsley and give it one more stir.
To serve, spread some Lemon Tahini Dressing on a whole wheat or sprouted bun, add a generous amount of Sloppy Joe mixture and pile high with spinach and onions
Notes
This freezes well, so if you have extra, pop it in the freezer for another time.