Preheat the oven to 180℃ (top/bottom heat mode) or 170℃ with convection (I bake in this mode).
Line the baking pan with parchment paper or grease it with butter and sprinkle with breadcrumbs or flour.
Step 2 - preparing the batter
Transfer the softened butter to a large bowl and add the sweetened condensed milk.
Beat them together until fluffy - I beat for about 3 minutes on the highest speed of the mixer.
200 g butter, 250 g sweetened condensed milk
Combine the flour with the baking powder.
200 g all-purpose flour, 1 teaspoon baking powder
Add one egg and one tablespoon of flour at a time to the butter mixture and mix briefly on low speed - just until combined.
4 eggs
Finally, add the remaining flour in two portions and mix briefly - just until the ingredients are combined. Do not overmix, or your cake may turn out dense!
Stop mixing when you still see remnants of flour around the edges of the bowl - then just briefly mix them in with a spoon.
Pour the batter into the baking pan.
Step 3 - baking the cake
Place the pan with the cake in the preheated oven and bake for about 45-50 minutes - until a wooden skewer comes out clean.