Make the red cake batter

• Preheat the oven to 175°C and grease and line two cake pans.
• Cream 200 g of the softened butter with the granulated sugar until pale and fluffy.
• Beat in the eggs one at a time, then add the vanilla extract.
• Add the red food coloring and mix until the batter is a deep, even red.
• Fold in the sifted flour, baking powder and salt, alternating with the milk, until just combined.

Bake the cake layers

• Divide the batter evenly between the prepared pans and smooth the tops.
• Bake until a skewer inserted in the center comes out clean.
• Let the layers cool in the pans for 10 minutes, then turn out onto a cooling rack to cool completely.

Make the Swiss meringue buttercream

• Whisk the egg whites with the remaining sugar in a heatproof bowl set over a saucepan of simmering water until the sugar dissolves and the mixture reaches about 70°C.
• Transfer to the stand mixer and whip on high speed until stiff, glossy peaks form and the bowl is cool to the touch.
• With the mixer on low, add the remaining 140 g softened butter a piece at a time until the frosting is smooth and silky.
• Add a little red food coloring to tint the buttercream if desired.

Assemble and decorate

• Level the cooled cake layers and stack them with a layer of buttercream in between.
• Cover the whole cake with the remaining buttercream and smooth it with a spatula.
• Chill the cake briefly so the frosting sets.
• Top with fresh cherries to decorate.