01 -
Start by making your raspberry compote since it needs time to cool completely. Toss the raspberries, sugar, and lemon juice into a small saucepan and cook over medium heat with the lid on for about 3 minutes until the berries start to break down and release their juices. Give it a stir as it begins to simmer, gently mashing some berries with your spoon. In a tiny bowl, whisk the water and cornstarch together, then stir this mixture into the bubbling raspberries. Keep cooking and stirring until it thickens nicely. Remove from heat and strain through a fine mesh strainer if you want it seedless, though the seeds add nice texture. Let it cool completely and chill for at least 30 minutes before using.
02 -
Heat your oven to 350°F and line the bottoms of two 8-inch round cake pans with parchment paper circles. You can skip greasing the sides if you want extra height, as the batter will naturally cling to help the cake rise.
03 -
In a large mixing bowl, whisk together the cooled melted butter, oil, sugar, and lemon zest until it looks fluffy and well combined. The mixture might look like wet sand at first, but keep whisking. Beat in the eggs one at a time, making sure each is fully incorporated, then mix in the vanilla and sour cream until smooth.
04 -
In a separate bowl, sift together the flour, baking powder, baking soda, and salt, then whisk to distribute evenly. Gently fold the dry ingredients into the wet mixture until just combined, then add the milk in two additions, folding carefully between each. Finish with a light whisking to create a smooth batter, but don't overmix. Finally, fold in the fresh raspberries with a gentle hand.
05 -
Divide the batter evenly between your prepared pans and bake for 20-25 minutes, until the tops are lightly golden and a toothpick inserted in the center comes out clean. Transfer the pans to a wire rack and let the cakes cool completely before removing from pans.
06 -
In a medium bowl, whip the cream with an electric mixer until soft peaks form. Add the sugar and lemon juice, then continue beating until you get firm peaks. Gently fold in the chilled raspberry compote - don't worry if it looks streaky, as this creates a beautiful marbled effect. Keep this chilled until you're ready to assemble.
07 -
Beat the very soft butter in a large bowl with an electric mixer until it's incredibly smooth and fluffy. Gradually add the powdered sugar and vanilla, beating slowly at first to avoid a sugar cloud, then increase speed and beat for about 2 minutes until pale and airy. Slowly drizzle in the cream, one tablespoon at a time, beating until smooth and spreadable. Finally, gently beat in the room temperature raspberry compote on low speed - be careful not to overbeat as this can cause the frosting to separate.
08 -
Place one cake layer on your serving plate and spread the raspberry cream filling evenly across the top, reaching all the way to the edges. Carefully place the second layer on top, aligning the edges. Cover the entire cake with the raspberry buttercream, using an offset spatula to smooth the sides and create beautiful swirls on top. For extra flair, dollop small spoonfuls of additional raspberry compote on top and swirl them in. Finish with fresh raspberries and lemon slices for a stunning presentation.