Preheat oven at 250 degree C.
Take a bowl and put eggs and beat until it becomes a little bit foamy. Add vanilla essence and mix well.
Mix butter and sugar in a separate bowl with spoon than beat it with electric beater until form into a creamy batter.
Then add this butter in three badges in eggs while beating.
Mix baking powder in flour then shift flour in eggs mixture, gradually, and beat in until all is combined. Stir in pistachio.
Pour mixture in a 6/9 inches greased pan and reduce temperature to 200 degree C. bake for about 30 minutes.
Take it out from the oven, cool the cake completely. Cut into slices.
Keep the slices on the cookies sheet in a single layer.
Bake again for 10-12 minutes till they are browned and crusty.
Take off, cool down completely. Serve with tea.