Preheat oven to 350 deg f (180 deg c).

In a microwave safe bowl, melt chocolate and butter. Mix well so that there are no lumps. Cool thoroughly.

Mix egg and beat well with the chocolate.

Add sugar and mix until it's dissolved.

Add flour and fold gently with spatula till it's all mixed.

Prepare a loaf pan. Grease it well. Pour batter in the pan and make sure it spreads evenly. Tap it down hard on the kitchen counter 2-4 times to release any air bubbles.

Bake in preheated oven for 15 minutes.

Meanwhile, prepare the cake batter.

Beat butter and sugar with hand held mixer till pale and creamy (about 2 minutes).

Sift flour, baking powder, and salt.

Add eggs one at a time to butter mixture beating after each addition.

Add vanilla extract and mix.

Add flour in two parts alternating with addition of milk. Fold and cut batter gently with spatula (do not use hand mixer).

Remove brownie base from oven. Pour cake batter onto it and spread it as evenly as possible. Again tap it on counter.

Reduce temperature to 320 deg f (160 deg c). Place the loaf pan in the oven and bake for 30-35 minutes or until the cake is firm and wooden skewer when pierced in the cake comes out clean.

Remove from oven and let it cool down. Then transfer it to a wire rack to cool thoroughly.