Preheat the oven to 350. Set out eggs so they come to room temp. If using frozen blackberries make sure to drain well. Grease eighteen 2 1/2 inch muffin tins or line them with paper or foil liners.
In a bowl, stir together the butter, milk and eggs.
In a mixing bowl, sift together the flour, 1 1/4 cups of the sugar, the baking powder and the salt. Make a well in the center and pour in the milk mixture all at once; stir until blended. The batter will be lumpy: Do not overmix. Fold in the berries.
Divide the batter among the prepared cups and sprinkle the remaining 4 teaspoons of sugar over the batter.