Place the cauliflower florets in a food processor. Pulse several times, creating cauliflower rice, but don't process so much it becomes mushy. Add cauliflower rice to a large pan (at least 12 inches, or use a large pot).
Now add the walnuts and mushrooms to the food processor. Pulse a few times until they are a similar consistency as the cauliflower. Don't over process or you will have a paste. Dump them into the pan with the cauliflower.
To the pan, add 2-3 tablespoons olive oil, chopped onion, garlic, adobo sauce (or chili powder), soy sauce, cumin, smoked paprika and 1/2 teaspoon salt. Turn the heat to medium-high, and stir until well combined. Continue to cook, stirring every couple minutes, for 15-20 minutes. Taste; add more salt or spices as desired.
Remove from heat and serve in tacos, burritos, salads, quesadillas, nachos or anywhere else you like! We like crunchy or soft tacos with diced tomatoes, vegan cheese, vegan sour cream/avocados and lettuce.
To Bake: Preheat the oven to 350 degrees F and grease a large rimmed sheet pan. In a large bowl, mix together the processed cauliflower, walnuts, mushrooms and all other ingredients. Spread onto the pan and bake for 30-40 minutes, stirring once in the middle of baking. Remove from the oven and serve.