For Meringue Layers: Preheat oven to 275 degrees F.
Line 2 baking sheets with kitchen parchment cut to fit. On each of the pieces of parchment, draw 2 (8-inch) circles using a cake pan as a guide. Turn the parchment over with drawing face down on the pan. You should be able to still see the circles. Set aside.
In a mixing bowl, beat together egg whites, salt, and cream of tartar with an electric mixer on high speed until soft peaks are formed. Still beating on high speed, gradually add sugar and strawberry extract until the whites form stiff, but not dry, peaks.
Divide the meringue among the 4 circles drawn on the parchment. Using a rubber spatula, spread meringue to the edges of the circles. Bake in oven for 50 minutes. When meringues are done baking, turn off the oven leaving the meringues inside to dry.
For Lemon Filling: In a medium mixing bowl, whisk to combine nonfat milk, lemon pudding mix, and lemon zest. Whisk continually for 2 minutes until filling mixture starts to thicken. Cover with plastic wrap and refrigerate for at least 1 hour.
For Strawberry Filling: In another medium mixing bowl, gently fold sliced strawberries into 1/2 container of whipped topping. Cover with plastic wrap and refrigerate until ready to assemble dacquoise.
Assembly: For best results, assemble dacquoise right before serving. Place 1 meringue circle on a cake plate. Evenly spread half of the lemon filling. Top with another meringue circle and spread with strawberry mixture. Repeat with another meringue circle and lemon filling. Place final meringue circle and top with remaining whipped topping. Garnish with mint sprig and fresh strawberries.