Preheat oven to 350 degrees.
Layer 3 tortillas in the bottom of a well-greased 9 by 12 by 2-inch casserole dish and coarsely crush the tortillas leaving fairly large sized pieces. Layer with 1/2 the sauteed mushrooms, 1/2 the tomatoes, and 1/2 the scallions, then sprinkle with 1/2 cup of cheddar.
Using your hands, compress the layers so that the ingredients are tightly packed. Moisten layer with 1/2 cup of the veloute. Repeat the process with the tortillas, mushrooms, tomatoes, scallions, and cheddar, again pressing firmly to tightly pack the ingredients. Crush the remaining tortillas on top, then moisten with remaining veloute and top with the remaining cheddar.
Cover with parchment and aluminum foil and bake about 45 minutes, or until cooked throughout and all cheese is melted. Cool and cut into individual servings.
For Chorizo Chilequiles: Add 1 1/2 chorizo on the bottom 2 layers and delete the scallions and tomatoes.
Make a medium dark roux with the oil and flour. When the roux is cooked, whisk in the tomato paste, chili powder, and garlic. Using room temperature chicken stock, begin to work the chicken stock into the roux adding a little at a time until each addition is fully incorporated. Continue until all the chicken stock has been added, then bring to a simmer for 10 minutes until the sauce is completely incorporated. Strain the sauce through a fine mesh strainer. Adjust seasoning with salt and pepper.
Yield: 1/2 quart
In a blender puree all ingredients. Serve with Exotic Mushroom Chilequiles.
Yield: 1 cup