I found this recipe some time ago on the the internet, but I have not tried it out, yet.
Master Buttermilk Fruit Muffin Mix
A perfect base for apple, banana, blueberry, or cranberry muffins - you name it.
10 C. unbleached all-purpose flour
1 C. buttermilk powder
6 C. light brown sugar - packed firmly
1/4 C. orange zest - very finely minced
8 t. baking powder
4 t. baking soda
1 1/2 t. salt
1 t. cinnamon
In a large bowl, whisk together flour, buttermilk powder, brown sugar, orange zest, baking powder, baking soda, salt and cinnamon. Pack into three cup bags.
To make muffins:
3 C. muffin mix
1/2 C. oil or melted, unsalted butter
1 C. water
1 egg
1 t. vanilla
1 1/2 C. fruit chunks (see below)
Stir together mix, oil, water, egg and vanilla. Fold in fruit. Scoop into prepared muffin tins, using a large ice-cream scoop. Bake at 375°F. for 25 minutes.
Makes 9-12 muffins. Top with chopped walnuts and brown sugar, before baking, if desired.
Fruit:
coarsely chopped cranberries, 1/2 inch chunks of banana, semi-frozen blueberries, diced apples or rhubarb, chopped dates - or any combination such as banana chunks with coarsely chopped cranberries. For a plain, coffee-cake-like muffin, omit fruit and layer muffin batter with streusel, topping with additional streusel.