Big Blueberry Muffins

Preheat oven to 400 degrees F. Place 12 round mousse rings on large heavy flat baking sheet and spray insides with nonstick spray. Using electric stand mixer, blend flour, sugar, butter and salt in large bowl until mixture resembles fine meal. Reserve 1/2 cup of mixture in small bowl. Add baking powder, baking soda and mace to remaining flour mixture in large bowl. Whisk buttermilk, eggs and vanilla to blend in medium bowl. Gradually beat into flour mixture. Carefully and evenly fold in blueberries. Divide batter evenly among prepared rings. Sprinkle streusel over tops of muffins.

Bake until golden brown and tester inserted in center comes out clean, about 25 minutes for fresh berries and 35 minutes for frozen. Cool 5 minutes on baking sheet.

Using spatula, carefully transfer muffins to rack and cool until warm. Starting at bottom, run small, sharp knife around edge of muffin to loosen and remove ring.

DO-AHEAD: Muffins can be made 2 days ahead. Store airtight at room temperature. Rewarm in 275 degrees F oven for 10 minutes, if desired.