I got this recipe from the Nourishing Gourmet.
2 c sourdough starter (I had a "scant" 2 cups once I took on cup out to feed for future use)
3 c whole wheat flour
1 c water
Combine these the night before, cover & leave on counter overnight.
In the morning, preheat oven to 400 F. Add the following to your flour mixture:
1 t salt
1/2 c melted coconut oil
1/2 c maple syrup
1 t vanilla
1 tsp cinnamon
1/4 to 1/2 t (I used a 1/2 t measure but didn't fill it full) ground nutmeg
1 t baking soda
Stir till thoroughly combined. Fold in 1 1/2 c fresh or frozen blackberries (I had a pint jar in the freezer, I used the whole thing, didn't bother to measure it). Fill greased muffin tins (I use stoneware) about 2/3 full. Bake 25 min, until slightly browned & toothpick comes out clean. Let cool in pan 5 min, then remove.
I got 12 regular muffins (pampered chef stoneware muffin pan) & I think 6 slightly smaller (I have an enamel covered heart shaped muffin pan that I used for the "overflow") muffins out of this. Girls ate 3 each, I'm congested so not tasting very well, but they seemed good. I would guess this recipe could be used with pretty much any fruit :)