Fry potatoes and peppers in the fat in a large frying pan for a few minutes. (Or use two smaller pans and fry ½ set in each.)
Sprinkle on the basil.
Pour the egg mixture into the pan and fry on medium heat. Lift and stick in a few places so that loose batter can run down and set. The frittata is ready when it has settled but is still creamy on the surface.