Preheat the oven to 425 degrees F. Place the cauliflower on a baking sheet.
Drizzle with the olive oil and toss. Sprinkle on the chipotle chili powder, smoked paprika, cumin and a big pinch of salt and pepper. Roast for 15 to 20 minutes, until golden.
While the cauliflower roasts, make the enchilada sauce.
Heat a large saucepan over medium heat and add the olive oil. Whisk in the flour and cook until it is golden brown, about 2 minutes. Add the remaining ingredients and whisk together, bringing the mixture to a simmer. Reduce the heat to low and cook for 5 more minutes before using.
Spray a 9×13 inch baking dish with nonstick spray. Take about ½ cup of enchilada sauce and spread it on the bottom of the dish. Take a large plate and add ⅓ cup of enchilada sauce on it.
Take each tortilla and dip it into the enchilada sauce on the plate. Fill it with a spoonful of the cauliflower and a handful of the cheese. Roll up the tortilla and place it in the dish – I like to do two rows of 6 or 7 tortillas. Repeat with remaining tortillas. Cover the tortillas with the sauce that is left and then sprinkle with the remaining cheese. If there is cauliflower left, you can add it on top too.
Reduce the oven heat to 400 degrees F.
Bake for 20 minutes, or until the cheese is bubbly and melty. Serve immediately with your desired toppings.