Fresh seasonal berries lend both vibrant color and taste to this pie, but frozen berries will work, as well.
1 1/2 cups graham cracker crumbs (about 12 cookie sheets)
3 tablespoons butter, melted
2 tablespoons 2% reduced-fat milk
3 cups blackberries
1/4 cup fresh lemon juice
1/4 teaspoon salt
4 large egg whites
1 cup plus 2 tablespoons sugar
6 tablespoons water
Fresh blackberries (optional)
Fresh mint sprigs (optional)
How to Make It
Combine first 3 ingredients in a bowl; toss with a fork until moist. Press into bottom and up sides of a 9-inch springform pan coated with cooking spray.
Combine 3 cups blackberries and fresh lemon juice in a blender; process until smooth. Strain mixture through a sieve over a bowl; discard solids.
Place salt and egg whites in a large bowl; beat with a mixer at high speed until foamy. Combine sugar and 6 tablespoons water in a medium saucepan; bring to a boil. Cook, without stirring, until a thermometer registers 250°. Gradually pour the hot sugar syrup into egg white mixture, beating at medium speed, then at high speed, until stiff peaks form. Gently fold in blackberry mixture; pour into prepared crust. Cover; freeze 8 hours or overnight. Let stand 5 minutes at room temperature before serving. Garnish with fresh blackberries and mint, if desired.