For The Sauce:

In a sauce pan melt butter.

Add brown sugar and cream.

Mix well and allow it to boil.

Add lemon juice and mix until combined.

Remove from flame and add vanilla and salt.

Mix well and allow it to cool.

For The Cake:

Preheat oven to 180°C.

In a bowl mix together maida, baking powder and baking soda and set aside.

In another bowl cream butter.

Add in vanilla essence and brown sugar and beat until light and creamy.

Add butterscotch sauce and beat well.

Add yogurt and beat.

Finally add the flour mix and milk until all the ingredients are combined to form a thick batter.

Line, grease and dust two 6" round pans and transfer the batter to them.

Bake in the oven for 30 - 35 minutes or until a tooth pick inserted comes out clean.

Allow it to cool a little, flip it on to the wire rack, remove the tin and klining paper and cool them completely.

For The Frosting:

Beat butter and vanilla until fluffy.

Add in the sauce and beat until they are combined well.

Add icing sugar in three portions, mixing every time with a spoon and then with a beater until well incorporated.

Once the whole frosting is creamier, set it aside until assembling.