Whole Wheat Banana Nut Muffins

The scenario:
2 bananas sitting on the table, rapidly turning brown
My all-purpose flour container, almost empty
My bag of whole wheat flour, FULL
What to do?
Whole wheat banana nut muffins! Mmm, I should've known the subtle sweetness of whole wheat flour would go perfectly with the taste of overripe bananas. Add to that a tangy zing of dried cranberries and a delicate crunch from toasted walnuts... It's the perfect muffin! It's not too sweet, so you don't feel guilty about eating it for breakfast. My only complaint was that the banana flavor was mild. But I think that let the flavor of the whole wheat flour shine through. So, I guess I have no real complaints after all!
The original recipe is from Betty Crocker: Baking for Today. It uses all-purpose flour, but I substituted whole wheat flour for most of the AP flour. The original also adds a streusel topping. You can do that if you want a sweeter muffin, but I omitted it.

Whole Wheat Banana Nut Muffins (adapted from Betty Crocker: Baking for Today)
12 muffins (or about 10-11 if you fill the cups to the top)

1/3 cup milk
1/4 cup vegetable oil
1 egg
1 1/2 cups whole wheat flour
1/2 cup all-purpose flour
1/2 cup light brown sugar
2 teaspoons baking powder
1/2 teaspoon salt
1 cup mashed bananas (about 2 medium)
1/3 cup dried cranberries
1/3 cup toasted walnuts, chopped
Streusel topping, optional (recipe below)

1. Preheat oven to 400 degrees F. Line a 12-cup muffin pan with paper liners or use nonstick spray.
2. Make streusel topping; set aside.
3. In large bowl, beat milk, oil, egg, and mashed bananas with fork or wire whisk. Stir in flour, sugar, baking powder, and salt all at once just until flour is moistened (batter will be lumpy). Fold in cranberries and walnuts. Divide batter evenly among muffin cups. Sprinkle each with about 1 tablespoon streusel topping, if using.
4. Bake 20-25 minutes or until golden brown (Mine didn't take near that long! I think they were done at about 17-18 minutes. Check them with a toothpick.). If baked in greased pan, let stand about 5 minutes in pan, then remove from pan to wire rack; if baked in paper baking cups, immediately remove from pan to wire rack. Serve warm if desired.

Streusel Topping
1/4 cup all-purpose flour
1/4 cup light brown sugar
1/4 teaspoon ground cinnamon
2 tablespoons firm butter or margarine

In medium bowl, mix flour, brown sugar, and cinnamon. Cut in butter, using pastry blender (or pulling 2 table knives through ingredients in opposite directions), until crumbly.