Preheat oven to 375 degrees Fahrenheit. Line a 12 cup muffin pan with cupcake liners (or grease well).
Add yogurt and granola to a bowl. Combine dry ingredients and add them to the bowl. Combine wet ingredients and add them to the bowl.
Fold in blueberries. Divided batter between muffin cups.
Prepare the streusel. Combine granola, brown sugar, and butter/margarine in a bowl. Knead with your fingers until ingredients come together to form a streusel. Sprinkle over muffins.
Bake for about 15 minutes, until tops are firm.