Preheat oven to 350°F/180°C.
In a mixing bowl, mix flour, milk, sour cream, eggs, herbs, butter and seasoning and set aside.
Preheat an 8-in. frittata pan with slide nonstick for about 1 minute. Pour olive oil over pan surface and heat for an additional minute.
Sauté scallions and garlic until soft. Add vegetables to the scallions and garlic.
Pour egg mixture on top and cover with crumbled feta. Bake in the oven for 40 - 45 minutes.