Banana Chocolate Chip Muffins with Cinnamon Streusel

Bahan-bahan (12 porsi)

• 2 and 1/2 teaspoons ground cinnamon
• 1/4 cup (50g) packed light or dark brown sugar
• 3/4 cup (135g) semi-sweet chocolate chips
• optional: 1/2 cup (60g) chopped walnuts
• 1 and 2/3 cups (208g) all-purpose flour (spooned & leveled)
• 1/2 teaspoon ground cinnamon
• 3/4 teaspoon baking soda
• 3/4 teaspoon baking powder
• 1/4 teaspoon salt
• 6 Tablespoons (85g) unsalted butter, softened to room temperature
• 1/2 cup (100g) granulated sugar
• 1 large egg, at room temperature
• 1 and 1/2 cups (345g) mashed bananas (about 4 medium or 3 large bananas)
• 1/4 cup (60g) plain yogurt or sour cream (I use nonfat Greek yogurt)