what to add for getting nice taste in cake?

Hi rajka, I'd recommend all spice, ginger or cinnamon as they all a bit of bite and flavour and enhance the taste of fruit in cake. Also almond oil is good, and actual oils are much better than essences and only a drop is needed.

It depends really with what flavor your cake is to be. But having had experience with baking, it always pays to have very good ingredients as a start. Fresh eggs, good quality butter, quality chocolates and flour, and following the recipe to the dot (on the first few tries). But I could definitely say, it's about the butter. Good luck!

Add vanilla. If it's chocolate cake, add chocolate chips.