Preheat the oven to 400°F. Prepare a muffin tin with paper liners, or spray with nonstick spray
MAKE THE MUFFIN BATTER:
In a large bowl, whisk together the dry ingredients. Add the remaining ingredients up to and including the egg. Carefully stir in the raspberries. Scoop the batter into the prepared muffin tins.
MAKE THE STREUSEL:
Combine the remaining ingredients in a small bowl. Use a fork to mix the butter into the dry ingredients and create crumbles. Top each muffin cup full of batter with a spoonful of streusel topping.
BAKE THE MUFFINS:
Bake for 15 to 20 minutes, or until a toothpick inserted into the center comes out clean.