12 T. ( 1 1/2 sticks) unsalted butter, softened, plus extra for pan
2 1/4 cups flour, plus extra for pan
4 tsp. baking powder
1 tsp. salt
1 cup whole milk
2 tsp. vanilla
6 large egg whites
1 3/4 cups sugar
Syrup and Topping
4 cups frozen strawberries
6 T. sugar
2 T. orange juice
1/2 cup water
2 T. strawberry flavored gelatin
2 cups heavy cream
Preheat oven to 350 degrees. Grease and flour 9x13 pan. Whisk flour, baking powder, and salt in bowl. Whisk milk, vanilla and egg whites in large bowl. With electric mixer on med-high beat butter and sugar til fluffy. Add flour mix and milk mix alternately ,in two batches, beating after each addition til combined. Pour into prepared pan and bake til toothpick near center comes out clean about 35 minutes. Cool cake in pan completely about 1 hour. Once cool cake can be wrapped in plastic at room temp for up to 2 days.
Syrup and topping: Heat 3 cups strawberries, 2 T. sugar, juice and water in med. saucepan over med-low heat. Cover and cook til liquid is deep red and strawberries are softened, about 10 min. Strain liquid into bowl, reserving solids, then whisk gelatin into liquid. Let cool to room temp, at least 30 min.
Meanwhile, poke about 50 holes in top of cooled cake (using skewer). Slowly pour liquid evenly over top of cake. Wrap with plastic wrap and chill in fridge til gelatin is set, at least 3 hours or up to 2 days. Pulse reserved strained strawberries, 2 T. sugar and remaining frozen strawberries in food processor til mix resembles jam. Spread evenly over cake.
With electric mixer on med-high speed, beat cream with remaining sugar to soft peaks. Spread cream over strawberries.