Preheat the oven to 350°F.
In a large bowl, using an electric mixer, beat the sugar and butter until fluffy.
Add the eggs one at a time, mixing well after each addition.
Add the flour and baking powder; mix gently.
Butter and flour a cake pan. Pour in the cake batter.
Bake for 35 minutes.
Poke the center with the tip of a knife. If the knife comes out clean, remove the cake.
Place the cake on a rack and let cool for 5 minutes before unmolding. Serve warm or cold.