Heat oven to 350º. Grease and flour a 9-x-13-inch baking pan.
In a mixing bowl, combine flour, onion, herbs, and bacon. In a small bowl, whisk the eggs with oil and pimientos; mix with dry mixture and stir until blended. Fold in the cheeses and squash. Spread in a baking pan and cover with crushed fried onions.
Bake 25 minutes or until set and lightly browned around the edges. Cool slightly and cut into squares. Serve with tomato salsa on the side, if desired.