Preheat your oven to 180°C for 10 minutes.
In a bowl, sift together the plain flour, baking powder, salt, and vanilla powder. Set aside.
In a separate large bowl, whisk the eggs until they become pale and frothy.
Pour in the oil and whisk for about 10 seconds.
Add the sugar and continue beating until the mixture looks light, airy, and creamy (about 1–1½ minutes).
Gradually fold the dry ingredients into the egg mixture, mixing only until combined.
In a small saucepan, gently heat the milk and butter until the butter melts completely. Do not allow it to boil.
While still warm, add the milk-butter mixture to the batter in 2–3 additions, folding gently after each addition. Avoid overmixing.
Transfer the batter to a greased and parchment-lined baking tin. Lightly tap the pan on the countertop to release any trapped air bubbles.
Sprinkle chopped nuts over the top, if desired.Bake for 25–30 minutes at 180°C, or until a skewer inserted in the center comes out clean.
Let the cake rest in the pan for about 10 minutes after baking before removing it.
Allow it to cool completely before slicing, serving, or storing.