I preheat the oven to 350°F (175°C) and grease two 9-inch round cake pans, lining the bottoms with parchment for easy release of this fluffy vanilla cake.

In a medium bowl, I whisk 2½ cups flour, 2 tsp baking powder, ½ tsp baking soda, and ½ tsp salt, ensuring even leavening for a light celebration cake.

In a large bowl, I cream ¾ cup butter and 1½ cups sugar with a mixer until pale and fluffy, about 3–4 minutes, for a tender Cake Costco Copy Cat crumb.

I beat in 3 eggs one at a time, scraping the bowl, then add 2 tsp vanilla extract for that signature bakery-style cake flavor.

In a small bowl, I mix ¾ cup sour cream and ¾ cup milk until smooth, ready to blend into this fluffy vanilla cake batter.

I alternate adding the flour mixture and sour cream mixture to the butter mixture, starting and ending with flour, mixing on low until just combined to keep this celebration cake tender.

I divide the batter evenly between the pans, smooth the tops, and bake for 30–35 minutes until a toothpick shows a few moist crumbs. I cool the cakes in pans for 10 minutes, then transfer to a wire rack to cool completely for this bakery-style cake.

I whip 2 cups heavy cream with ½ cup powdered sugar, 1 tsp vanilla, and 1 tbsp pudding mix (if using) until stiff peaks form, creating a stable frosting for this fluffy vanilla cake.

I place one cake layer on a plate, spread with whipped cream and sliced strawberries (if using), top with the second layer, and frost the top and sides with whipped cream, swirling for a festive Cake Costco Copy Cat look.