Preheat your oven to 350°F and line a 9-inch round cake pan with parchment paper. Grab a medium bowl and whisk together flour, baking powder, and salt. Set it aside while you move to the next step.
In a large bowl, cream together softened butter and granulated sugar for about 2 minutes until it's light and fluffy. You'll know it's ready when it looks pale and airy. This is the foundation of your strawberry shortcake family 4th july, so don't rush it.
Add eggs one at a time, beating well after each one so they fully incorporate. Then pour in your vanilla extract and mix for another 30 seconds. The mixture should look smooth and creamy now.
Alternate adding the dry ingredients and milk to the butter mixture, starting with flour. Add one-third of the flour, then half the milk, then another third of flour, then the rest of the milk, and finish with the last of the flour. Mix on low speed just until combined—don't overmix or your cake gets tough.
Pour the batter into your prepared pan and bake for 22-25 minutes until a toothpick inserted in the center comes out clean. I always check mine at 22 minutes because my oven runs hot, so keep an eye on it. The top should be golden brown and spring back when you lightly touch it.
Let the cake cool completely on a wire rack for at least 20 minutes before you even think about frosting it. Mine always sticks a little to the pan edges, and that's totally fine—just run a thin knife around the sides gently. Transfer it to a serving plate when it's completely cool.
While the cake cools, whip together heavy cream and powdered sugar in a chilled bowl until stiff peaks form. This takes about 3-4 minutes with an electric mixer on high speed. Gently fold in the lemon zest at the very end.
Top your cooled cake with sliced strawberries, then spread or dollop the whipped cream on top. Slice into 8 pieces and serve immediately—this is when it tastes absolutely incredible.