Preheat oven to 350°F.

In a medium bowl, whisk flour, baking powder and salt until combined. Set aside.

Using a stand mixer, beat sugar, oil, eggs, egg whites, and extracts until combined. Then add the sour cream and beat until combined. Add half of the flour mixture, mixing until just combined. Slowly add milk, then the remaining flour. Scrape bowl as needed. Avoid overmixing.

Grease a 9x13 metal baking pan and pour batter into it, spreading evenly. Tap the pan on the countertop a few times to remove air bubbles.

Bake for 25-30 minutes until a toothpick comes out clean. Rotate the pan if necessary. Cool completely on a rack.

In a large mixing bowl, combine cream cheese, powdered sugar, and vanilla extract. Beat until smooth. Slowly pour in the heavy cream while mixing. Scrape down the bowl as needed. Increase speed to high and whip until stiff peaks form.

Spread the frosting onto the cooled cake. If serving immediately, stir the strawberries with jam and spoon over the top. If not, refrigerate the frosted cake and add strawberries right before serving.