Preheat oven to 350°F (175°C). Grease a 4-inch round or square pan. Whisk flour, baking powder, and salt. In another bowl, cream the 1/2 cup butter and granulated sugar until fluffy, then beat in egg and 1 tsp vanilla. Alternately add dry ingredients and milk, mixing until just combined. Pour into pan.

Bake 20 to 22 minutes until a toothpick comes out clean. Cool in pan 10 minutes, then turn onto a wire rack to cool completely.

For buttercream, beat the 1/4 cup butter until smooth, gradually add powdered sugar, then 1 tsp vanilla and 1 tbsp cream. Beat until fluffy. Reserve 3 tbsp and tint black with gel coloring.

Level the cake top, split horizontally. Fill with white buttercream, apply a thin crumb coat, and chill 15 minutes.

Spread final white buttercream layer. With black buttercream in a piping bag with a small round tip, pipe Snoopy’s nose, eyes, smile, and collar.

Place cake in bento box or on a plate. Serve at room temperature.