1. Preheat the oven to 350°F (175°C) and line an 8×8-inch baking pan with parchment paper.

2. In a mixing bowl, cream the butter and sugar together until pale and fluffy (about 3–5 minutes).

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

4. Stir in the vanilla extract.

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

6. Gradually add the dry mixture to the butter mixture in three parts, alternating with the milk in two parts.

7. Mix until just combined, avoiding overmixing.

8. Pour the batter into the prepared pan and smooth the top with a spatula.

9. Bake for 30–35 minutes or until a toothpick comes out clean.

10. Cool in the pan for 10 minutes, then transfer to a rack. Dust with powdered sugar once fully cooled.