Preheat oven to 350°F (175°C). Grease a 9-inch cake pan and line the bottom with parchment paper.
Beat butter and sugar together for 3–5 minutes until light and fluffy.
Add eggs one at a time, beating well after each. Mix in vanilla extract.
Whisk flour, baking powder, and salt. Add to wet ingredients on low speed until just combined.
Pour in milk and mix until smooth. Do not overmix.
Transfer batter to pan and bake for 40–50 minutes, until golden and a toothpick comes out clean.
Cool in pan for 10–15 minutes, then transfer to wire rack. Serve plain or dusted with powdered sugar.