Start by heating the oven to 350°F. Grease two 8-inch round cake pans and give them a light dusting of flour. I also like to line the bottoms with parchment paper because it makes removing the cake layers much easier. Set the pans aside while you prepare the batter.

Add the vanilla cake mix, water, vegetable oil, eggs, and vanilla extract to a large mixing bowl. Beat everything until the batter looks smooth and creamy. Take a quick look around the bottom and sides of the bowl to make sure no dry cake mix is hiding there.

Pour the batter into the two prepared pans. Try to keep the amounts close so the layers bake evenly. Give the pans a gentle tap on the counter once or twice. This settles the batter and helps get rid of any larger air pockets.

Place both pans in the hot oven and bake for 30 to 35 minutes. Start checking around the 30-minute mark. Insert a toothpick into the center of a cake layer. If it comes out clean or has just a few moist crumbs, the cakes are ready.

Let the cakes sit in their pans for about 10 minutes after coming out of the oven. Turn them carefully onto a wire rack and remove the parchment paper. Give the layers plenty of time to cool before frosting. Warm cake can make the frosting soft and difficult to spread.

Place the fresh raspberries in a bowl and mash them gently until they become juicy. For a smoother frosting, press the berries through a fine-mesh strainer to remove the seeds. Measure the raspberry pulp after straining so you know exactly how much is going into the frosting.

Beat the softened butter and cream cheese until smooth and creamy. Add the powdered sugar gradually, mixing as you go. Add the raspberry pulp, lime juice, and salt, then beat until the frosting looks thick and easy to spread. If the frosting seems a little soft, pop it into the refrigerator for a short while before decorating the cake.

Place one completely cooled cake layer on a serving plate. Spread a generous layer of raspberry cream cheese frosting over the top. Set the second cake layer on top and cover the cake with the remaining frosting.

Smooth the top and sides, then add a few fresh raspberries if you want a pretty finish. I like to chill the cake before cutting it because the frosting sets nicely and the slices come out cleaner.