To make raspberry syrup, thaw berries but do not drain. Place the berries in a blender container or food processor bowl. Cover and blend or process until berries are smooth. Press berries through a fine-mesh sieve into a small saucepan. Discard seeds. Cook and stir juice over medium heat until just heated through. Stir in maple syrup; set aside.

To make pancakes, in a medium mixing bowl stir together flour, baking powder, lemon peel, and salt. Make a well in the center of flour mixture; set aside. In a small mixing bowl beat egg yolk slightly. Stir in melted butter and milk. Add egg yolk mixture all at once to the flour mixture. Stir just until moistened (batter should be lumpy).

In another medium mixing bowl beat egg whites with an electric mixer at medium speed until stiff peaks form (tips stand straight). Gently fold egg whites into flour mixture, leaving a few fluffs of egg white*. Do not overmix.

For standard-size pancakes, pour 1/4 cup batter onto hot, lightly greased griddle or heavy skillet. (Or, for dollar-size pancakes, pour about 1 tablespoon batter onto hot, lightly greased griddle or heavy skillet.) Cook over medium heat 2 minutes per side or until pancakes are golden brown. Turn to second side when pancakes have bubbly surfaces and edges are slightly dry. Repeat with remaining batter. Serve with raspberry syrup, butter, and fresh raspberries, if desired. Makes 8 (4-inch) pancakes or 20 (2-inch) pancakes.

When folding egg whites, use a rubber spatula. Cut down through the middle of the mixture and sweep upward; give the bowl a quarter turn before repeating. Continue until mixed.

Nutrition facts are for 1 large pancake.