Preheat the oven to 400°F. In a large bowl, combine the flour, sugar, baking powder, baking soda and salt.
In another bowl, combine the eggs, yogurt, oil and lemon zest; mix well.
Stir the wet ingredients into the dry ingredients just until moistened. Fold in the raspberries.
Fill 12 greased or paper-lined muffin cups about three-fourths full with the batter.
For the topping, combine the sugar and flour. Cut in the butter until the mixture resembles coarse crumbs. Sprinkle about 1 tablespoon over each muffin.
Bake for 18 to 20 minutes or until the muffins are done. Cool in the pan for 10 minutes before removing them to a wire rack.
