Two simple recipes to make a Bisquick-like baking mix from scratch are available from Gourmet Sleuth and Food Network. Each uses all-purpose flour, baking powder, salt and shortening. Use this mixture in recipes calling for either Bisquick or an all-purpose baking mix.
Food Network's recipe yields 7 cups. It combines 6 cups of flour, 3 tablespoons of baking powder and 1 tablespoon of salt in a food processor, pulsing with the shortening to achieve a cornmeal texture. Alternatively, a fork can be used to cut the shortening into sifted flour, baking powder and salt.
The Gourmet Sleuth recipe uses the same ingredients but in slightly different proportions, combining 1 cup of flour, 1 1/2 teaspoons of baking powder, half a teaspoon of salt and 1 tablespoon of shortening all at the same time in a food processor.