Sourdough Blueberry Crumb Muffins

Sourdough Blueberry Crumb Muffins: Preheat oven to 400 degrees (200 degrees C). Grease muffin cups or line with muffin liners. The recipe that appears here makes 6 large size muffins. These muffins are great without the sourdough starter also (just in case you don't have any).
MUFFINS: Mix together 1 & 1/2 cups all purpose flour+3/4 cup sugar+1/4 tsp salt+2 tsp baking powder & set aside. In mixing bowl, add 3/4 cup sourdough starter+1/3 cup vegetable oil+1 egg+1/3 cup milk-mix well-gradually add dry ingredients-mixing well. (Batter will be a little stiff). Gently fold in 1 cup fresh blueberries and 1/4 cup snipped dates. Spoon batter into each muffin cup filling it nearly to the top.
TOPPING-1/2 cup sugar-1/3 cup flour-1/4 cup very soft butter (I used unsalted) and 1 & 1/2 tsp cinnamon-mix all together well and sprinkle on top of mufins before baking. Press crumb topping gently into muffins.
Bake 400 degrees for 20-25 minutes until toothpick comes out clean when stuck in center of a muffin. Cool on wire rack. Hide a muffin for yourself for later-because they will disappear really quick.

VARIATIONS:
Cranberry-Orange: substitute 1 cup dried cranberries+1 small can well drained mandarin oranges cut into small pieces+1/3 tsp fresh orange zest for blueberries/dates.
Apple-Raisin:substitute 1 & 1/2 cup fine chopped apple+1/4 tsp cardamom+1/3 cup raisins for blueberry/date mix, and add 1 tsp cinnamon and 1/8 tsp nutmeg.