1. Preheat oven to 400°F. Butter a muffin pan. Combine 1/4 cup sugar with 1/4 teaspoon cardamom; liberally sprinkle muffin tins with sugar mixture. Save remaining mixture for topping muffins.
2. Sift 2 1/4 cups all-purpose flour, remaining 3/4 cup sugar, baking powder, remaining 3/4 teaspoon cardamom and salt together.
3. Add chilled, cut butter to dry ingredients and cut in with pastry blender or two knives. (You can also use an electric stand mixer fitted with the paddle attachment on low speed.) Stop mixing when the butter pieces are pea-sized and smaller.
4. Whisk buttermilk with eggs and vanilla. Add to dry ingredients stirring just until combined. The batter will be lumpy.
5. Measure out 1/2 cup each of blackberries, blueberries and raspberries and save any leftover berries for another use, such as a smoothie or yogurt topping.
6. Toss 1/2 cup each of the berries with remaining 1/4 cup all-purpose flour and gently fold into batter. Fill muffin tins to the top and sprinkle with a generous amount of remaining sugar mixture.
7. Bake 15 minutes and rotate pan. Bake 10 to 15 minutes longer or until muffins spring back when lightly pressed in the center and/or a cake tester inserted in the center comes out clean. Jumbo muffins will take approximately 5 minutes longer.

Amount Per Serving