01 - Preheat oven to 350°F. Grease and line a 9x13 inch rectangular cake pan with parchment paper.
02 - Whisk together flour, baking powder, and salt until evenly combined.
03 - Beat softened butter and granulated sugar with an electric mixer until light and fluffy, approximately 3 minutes.
04 - Add eggs one at a time, beating well after each addition. Stir in pure vanilla extract.
05 - Add dry ingredients in three increments, alternating with milk, beginning and ending with dry mixture. Mix until just combined.
06 - Pour batter into prepared pan, smooth the top, and bake for 30–35 minutes. Confirm doneness with a clean toothpick inserted in center.
07 - Allow cake to cool in pan for 10 minutes, then turn out onto wire rack to cool completely.
08 - Beat softened butter until creamy, gradually add powdered sugar and beat until smooth. Mix in vanilla extract and milk until spreadable consistency is achieved. Divide and tint with food colors as desired.
09 - Once cake is fully cooled, cut and arrange pieces into a house form using rectangles for walls and triangles for the roof.
10 - Apply colored buttercream to create walls, roof, and doors. Use candies and wafer cookies for embellishments. Add green coconut for grass if desired.
11 - Chill assembled cake briefly to allow decorations to set before serving.