Preheat your oven to 350°F (175°C). Grease and line three 8-inch round cake pans with parchment paper for easy removal. In a medium bowl, whisk together the all-purpose flour, baking powder, and salt. In a large mixing bowl, beat the granulated sugar and oil until well combined, then add the eggs and vanilla extract, mixing until fluffy. Incorporate the sour cream, followed by alternating the flour mixture and milk until just combined. Divide the batter evenly among the prepared pans.

Place the cake pans in the preheated oven and bake for 18-22 minutes. The cakes are done when a toothpick inserted into the center comes out clean and the tops are lightly golden. Once baked, remove the pans from the oven and let them cool in the pans for about 10 minutes. After that, carefully transfer the cakes to wire racks to cool completely.

While the cakes cool, take your fresh strawberries and slice them. Combine the sliced strawberries with a spoonful of strawberry jam in a medium bowl. Allow the mixture to sit for at least 15 minutes at room temperature.

In a mixing bowl, beat together the cream cheese and powdered sugar until smooth and creamy, about 2-3 minutes. Gradually pour in the cold heavy whipping cream and continue whipping on high speed until stiff peaks form, which should take about 2-4 minutes.

Start with one cooled cake layer on a serving plate. Spread a generous layer of whipped cream frosting over the top, followed by a layer of your macerated strawberries. Repeat with the second cake layer, then place the final layer on top. Use the remaining whipped cream frosting to cover the top and sides of the entire cake.

Once assembled, cover your cake with plastic wrap or a cake dome and refrigerate for at least 30 minutes.