Preheat the Oven: Preheat the oven to 350°F.
Combine the Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, and salt until evenly combined. Set the mixture aside.
Mix the Cake Batter: Using a stand mixer fitted with the paddle attachment, or a hand mixer, beat the sugar, oil, eggs, egg whites, vanilla extract, and almond extract until combined. Add the sour cream and mix until incorporated.
Add the Flour Mixture: Add half of the dry ingredients to the wet mixture and beat just until combined. With the mixer running, slowly pour in the milk, then add the remaining flour mixture. Scrape the bottom and sides of the bowl as needed, mixing only until the batter is combined. Avoid overmixing. Prepare the Cake Pans: Line three 8-inch cake pans with parchment paper and grease the pans. Divide the batter evenly among the prepared pans. Gently tap or drop each pan on the countertop a couple of times to release air bubbles.
Bake the Cake Layers: Bake the cakes for 18–22 minutes, or until a toothpick inserted into the center comes out clean. If needed, rotate the pans once during baking to promote even browning.
Cool the Cake: Transfer the pans to a wire rack and allow the cake layers to cool completely before assembling.
Prepare the Strawberries: Combine the 3 cups of strawberries with the strawberry jam. For the filling, about 2½ cups of the strawberries can be sliced, while about ½ cup can be diced for the top. Alternatively, all the berries may be sliced or diced according to preference. Beat the Frosting Base: Place the softened cream cheese, powdered sugar, and vanilla extract in a large mixing bowl. Using a stand mixer fitted with a whisk attachment, or a hand mixer, beat on medium speed until the mixture is smooth.
Add the Heavy Cream: While the mixer continues whipping, slowly pour the very cold heavy cream down the side of the bowl. Stop periodically to scrape the bottom and sides of the bowl.
Whip to Stiff Peaks: Increase the mixer speed to high and continue whipping until the frosting reaches stiff peaks. Keep the cream cold throughout this process so it thickens properly. If using a hand mixer, hold the bowl near the top rather than against your body. Build the First Layer: Place one cooled cake layer on a serving platter. Spread one-third of the whipped cream frosting over the cake, then add approximately 1¼ cups of the prepared strawberries.
Add the Second Layer: Place the second cake layer over the strawberries. Repeat the frosting and strawberry filling, using another one-third of the frosting and approximately 1¼ cups of strawberries.
Finish the Cake: Place the third cake layer on top. Spread the remaining whipped cream frosting over the top, then arrange the remaining strawberries in the center.
Garnish and Serve: Decorate the outside of the cake with additional whole strawberries, if desired.
