Cut cauliflower into roughly 1/2 inch pieces. Meanwhile, heat a large skillet over medium-high heat.

Place cauliflower in a large bowl and add olive oil, cumin, garlic, salt, and pepper, tossing to combine until cauliflower is evenly coated in spices. Add olive oil to the hot skillet and cook, tossing occasionally, until cauliflower have browned, about 5-7 minutes. Once they have cooked, remove cauliflower from the skillet and return them to the large bowl.

Once peppers have cooled enough to handle, peel off the blistered skin, cut off the tops, and remove the seeds. Cut the peppers into 1/2 inch pieces. Add the chopped peppers into the bowl with the cauliflower, and toss together until peppers and cauliflower are evenly distributed.

Make the sour cream sauce by melting the butter in a saucepan over medium heat. Add flour and whisk until combined. Let flour cook for about 1 minute, then whisk in vegetable stock. Bring to a simmer, and let simmer for about 2-3 minutes. Add sour cream, cayenne pepper, and diced jalapeños, and let simmer until thickened, about 2-3 additional minutes. Season to taste with salt.

Once the cream sauce is complete, it's time to start assembling the enchiladas! Pour just under 1/2 of the cream sauce into the bottom of a 9'x13' baking pan. Assemble the enchiladas by filling each tortilla with about 1/4 cup of the pepper and cauliflower mixture and a generous sprinkle of cheese. Place enchiladas side by side in the pan, seam side down. Pour remaining cream sauce evenly over enchiladas.

Cover the pan with aluminum foil, and bake for 20 minutes. Remove foil and bake uncovered for an additional 10 minutes.

Let cool slightly, and serve with sour cream, more crumbled cotija, lime slices, or sliced avocado.