-Preheat oven to 350F. Grease 6 muffin cups w/ butter. Line base with rounds of parchment paper to prevent sticking.
-Combine butter and granulated sugar in a bowl, beat with a mixer at medium speed until light and fluffy. Add eggs, one at a time, beating well.
-Fold flour, almonds and baking powder. Gently stir in milk and lime zest.
-Place a layer of blueberries in the bottom of each muffin cup. Fold remaining blueberries into the batter. Spoon batter into muffin cups.
-Bake about 25 minutes, until cakelets are springy to the touch. Remove from the oven and let cool. Run a sharp knife around the edge of each cakelet, then invert the pan. Remove parchment paper. Serve topped with coarse sugar and whipped cream.