Preheat your oven to 350°F (175°C).
Grease your cake pan with butter generously.
Dust it lightly with flour too.
This prevents sticking later on.
Beat softened butter in a bowl.
Add sugar and mix until fluffy.
This takes about 3-4 minutes.
The mixture should look pale yellow.
Crack one egg at a time.
Mix well after each egg addition.
Add vanilla extract and blend thoroughly.
The batter should be smooth now.
Mix flour, baking powder, and salt.
Do this in a separate bowl.
Stir them together with a spoon.
Add flour mixture to butter mixture slowly.
Pour some milk, then add more flour.
Keep alternating until everything is mixed.
Don't overmix the batter at all.
Pour batter into your prepared pan.
Smooth the top with a spatula.
Bake for 40-45 minutes in the oven.
A toothpick should come out clean.
Let the cake cool for 10 minutes.
Remove it from the pan carefully.
Let it cool completely before serving.