Preheat your oven to 350°F (180°C). Grease and line both 9-inch cake pans with parchment paper.

In a bowl, whisk together flour, baking powder, and salt.

Using an electric mixer, cream the butter and sugar together until light and fluffy (3–4 minutes).

Add eggs one at a time, mixing well after each.

Mix in vanilla extract.

With mixer on low, alternately add the flour mixture and milk to the butter mixture, beginning and ending with flour. Mix until just combined.

Divide the batter evenly between the two pans.

Bake for 25–30 minutes, or until a toothpick inserted in the center comes out clean.

Let cakes cool in pans for 10 minutes, then transfer to cooling racks.

While cakes are cooling, make the buttercream. Beat butter until light, then gradually add powdered sugar, salt, milk, and vanilla, beating until smooth.

Once cake layers are fully cool, level the tops with a serrated knife if needed.

Place first cake layer on a serving platter. Spread a layer of buttercream on top. Place the second cake layer on top.

Frost the entire cake with a thin coat of frosting (crumb coat). Refrigerate for 20 minutes.

Tint about half of the remaining frosting red. Using an offset spatula, frost the top half of the cake with red icing and the bottom half with white.

Roll out black fondant (or tint white fondant with black coloring) into a long strip and wrap it around the center of the cake as the Pokeball band.

Roll out white fondant and cut a 3-inch circle for the Pokeball button. Place it in the center stripe. Cut a smaller black circle and place it on top of the white circle.

Use any leftover frosting or fondant to tidy up edges and add extra Pokemon-themed decorations as you like.