If you can’t get fresh raspberries, you can use frozen. Just be sure to drain them well and pat with paper towels to remove excess moisture.
Preheat oven to 350 degrees F. Prepare muffin cups (spray with nonstick cooking spray or line with paper liners).
Sift together the flour, sugar, brown sugar, baking powder, salt, and cinnamon into a large bowl. Make a well in the center. Place egg, melted butter and milk in the well. Stir with a wooden spoon until ingredients are just combined; do not overmix. Quickly stir in raspberries and lemon zest. Divide batter among 12 muffin cups.
To make the topping, combine the coconut, sugar, flour, cinnamon and lemon zest in a small bowl. Pour over the melted butter and stir to combine. Sprinkle mixture evenly over each muffin.
Bake muffins approximately 20 to 25 minutes, until nicely browned and firm.
Let muffins cool slightly, remove from tins and place on a wire rack to cool for 10 minutes. Then, combine powdered sugar and lemon juice to make a smooth glaze. Drizzle over slightly warm muffins. Makes 12 muffins.