Cook tortillas, one at a time, for 15 seconds in hot bacon grease or oil. Place 2 tablespoons of cheese and 1 tablespoon of chopped onion on each tortilla and roll up. Place seam-side down in 11 by 7.5 by 4 cm dish. Melt butter and blend in flour. Add chicken broth and bouillon/water all at once. Cook and stir in sour cream and peppers. Pour over tortillas and bake in 220ºC . oven for 20 minutes. Add extra cheese and onion; bake an additional 5 minutes.