• Preheat oven to 350°. Lightly grease a muffin tin with non-stick cooking spray or vegetable oil, or line with paper muffin liners.
• Prepare streusel topping and set aside.
• In a small bowl, whisk together flour, baking powder, baking soda and salt; set aside.
• Combine banana, sugar, melted butter, sourdough starter, eggs and vanilla in a large mixing bowl; beat on medium speed until well blended. Add flour mixture to banana mixture, stirring just until moistened. Mix in cranberries.
• Divide batter evenly into 12 muffin cups. Sprinkle muffins with streusel topping.
• Bake for 20 minutes, until a tester inserted into the center comes out clean. Cool muffins for five minutes in the muffin pan before removing to a wire rack to cool.

Streusel Topping:

• In a small bowl, whisk together sugar and flour. Add butter and mix until mixture has a sandy texture. Mix in almonds.