Preheat oven to 400°F. Lightly dust work surface with 1 tablespoon of the powdered sugar. Unroll 1 piecrust on top of powdered sugar, and roll into a 12-inch circle. Use a 6-inch round cutter to cut 2 (6-inch) circles. Reroll the scraps once, and cut 1 more circle. Repeat procedure with remaining piecrust and powdered sugar to have a total of 6 mini piecrusts. Fit each circle into a 5-inch round mini pie pan; fold edges under, and crimp. Prick bottom and sides with a fork. Chill 15 minutes.

Place pie pans on a cookie sheet. Line each crust with a small square of parchment paper, and fill with pie weights or dried beans. Bake in preheated oven until crust is set and edges are lightly browned, 12 to 15 minutes. Carefully remove weights and parchment, and continue baking until crusts are golden brown, about 5 minutes. Remove to a wire rack, and cool until ready to use.

Process strawberries in a food processor until very smooth, 1 to 2 minutes. Strain pureed strawberries through a fine mesh strainer into a 2-cup glass measuring cup to get 1 1/2 cups juice (reserve any extra juice for another use). Discard solids. Stir together 1 1/2 cups strawberry juice and 1/2 cup of the granulated sugar in a small saucepan over medium. Bring mixture to a boil, and reduce heat to medium-low. Cook, stirring often, until mixture is reduced to 1 cup, 8 to 10 minutes.

Sprinkle unflavored gelatin over 1/4 cup cool water in a small bowl, and set aside. Whisk together egg yolks in a medium bowl, and slowly add about half of cooked strawberry juice mixture to yolks, whisking constantly. Slowly whisk yolk mixture back into strawberry juice mixture in pan. Cook, whisking constantly, until mixture has thickened slightly, 3 to 4 minutes. Whisk in unflavored gelatin mixture to combine. Whisk in strawberry gelatin, lemon juice, and salt to combine completely. Remove from heat, and transfer mixture to a large bowl. Chill mixture until thickened slightly, 1 hour to 1 hour and 15 minutes, stirring after 30 minutes.

Beat egg whites with an electric mixer on high speed, until soft peaks form, about 8 minutes. (Pasteurized eggs take longer to whip up than regular eggs.) Gradually add 1/4 cup of the granulated sugar, and beat until stiff peaks form, 2 to 3 minutes. Gently whisk strawberry mixture to incorporate any lumps. Gradually fold egg white mixture into strawberry mixture until thoroughly combined.

Beat 1 cup of the heavy cream with a heavy-duty stand mixer on high speed, using the whisk attachment, until foamy. Gradually add 1/4 cup of the granulated sugar, beating until stiff peaks form. Gradually fold whipped cream into strawberry mixture. Spoon mixture evenly (about 3/4 cups) into prepared piecrusts. Chill at least 4 hours or overnight.

Beat remaining 1 cup heavy cream with a heavy-duty stand mixer on high speed, using the whisk attachment, until foamy. Gradually add remaining 1/4 cup granulated sugar, and beat until stiff peaks form. Dollop or pipe whipped cream on top of pies, and garnish with small halved strawberries.