Nothing short of delicious!
Preheat oven to 375 degrees.
Start by making the pickled onions. Stir together the vinegar, water, sugar, and 1/2 teaspoon kosher salt in a bowl. Add the sliced onions. Let sit at room temperature while you prepare everything else.
Make the sauce by whisking all of the ingredients together. Place in refrigerator until ready to use.
Place shredded brussels sprouts and cabbage on a large cookie sheet with sides. Toss with extra virgin olive oil and season with kosher salt and pepper.
Roast in oven for about 25 minutes or until soft and brown. Stir a couple of times during cooking.
After 25 minutes, push all of the vegetables to one side of the cookie sheet. Add the beans to the other side of the cookie sheet to warm them and cook for 5 more minutes.
Also cover the stack of tortillas with tinfoil and place them in the oven for the 5 minutes while the beans cook.
Remove vegetables, beans and tortillas and prepare to assemble the tacos. Squeeze the juice from 1 lime all over the vegetables and beans.
Assemble the 8 tacos on a large tray and serve them open face.. On each taco, place roasted vegetables, beans, pickled onions, 2 avocado slices, cilantro, a sprinkling of cheese and a swirl of sauce.