Pre-heat oven to 425. Cut Brussels sprouts in half. Toss with EVOO, season with salt, pepper, chile powder, paprika, cumin, garlic, cayenne, and whatever else you like. Roast until soft, about 15-20 minutes. Meanwhile, slice a red onion thin. Pickle by covering onions with rice wine vinegar and water. Let sit. The longer the better. I keep a jar in the fridge. Assemble tacos by charring corn tortillas on stove top. Assemble by adding Brussels sprouts, onions, creme fraiche, avocado, and cheese. Sometimes I add cabbage or lettuce or even crushed tortilla chips if I have them.