I took this original recipe and made a few tweaks for a less sugary, more berry, less fat version.

Ingredients

1 1/2 cups all-purpose flour
1/2 cup white sugar
1/2 teaspoon salt
2 teaspoons baking powder
1/3 cup - 3 Tbsp vegetable oil
3 Tbsp Applesauce
1 egg
1/3 (or more) cup milk
1 cup fresh or frozen blueberries + 1/2 cup fresh or frozen mixed berries (no strawberries)
1/2 cup white sugar
1/3 cup all-purpose flour
1/4 cup butter, cubed
1 1/2 teaspoons ground cinnamon

Directions

1. Preheat oven to 400 degrees F (200 degrees C). Grease muffin cups or line with muffin liners.
2. Combine 1 1/2 cups flour, 1/2 cup + 2 Tbsp sugar, salt and baking powder. Place vegetable oil and applesauce into a 1 cup measuring cup; add the egg and enough milk to fill the cup. Mix this with flour mixture. Fold in blueberries. Fill muffin cups right to the top, and sprinkle with crumb topping mixture.
3. To Make Crumb Topping: Mix together 1/2 cup sugar, 1/3 cup flour, 1/4 cup butter, and 1 1/2 teaspoons cinnamon. Mix with fork, and sprinkle over muffins before baking. (I don't use all the topping in one batch - I save the rest in the fridge and use them over 2-3 batches)
4. Bake for 20 to 25 minutes in the preheated oven, or until done.