Dry mixture: Shift whole wheat flour, baking powder, baking soda, salt. Keep it aside.
Wet mixture: In a grinder add sugar, curd, oil, vanilla essence, and mix until smooth.
Mix dry mixture into wet mixture and mix well.

Put batter into a greased pan and tap the cake pan on a countertop to release any large air bubbles.
Put cake pan into the preheated pressure cooker and bake it for 1 hour.

Tips:

You can add 1/4 cup of mixed dry fruits and make dry fruit curd cake with the same recipe.
For making chocolate curd cake just add 2 tbsp of cocoa powder and chopped walnuts. Chocolate curd cake is ready.
Baking time may vary.
If cake batter looks dry, add 2- 4 tbsp of milk.
If baking in Oven: Bake in the preheated oven at 180 deg Celsius or around 360 Fahrenheit for about 1 hour. The baking time may vary. So keep checking the cake after 40 to 45 minutes.

Pressure Cooker Method:
Grease the baking tin with oil and dust it by sprinkling whole wheat flour over greased surface evenly. Pour the mixture into the greased baking tin.

Important Notes:

Use the baking tin of 6 inches in diameter, so that it can easily get into the pressure cooker.
Use a 5-liter pressure cooker. It should be big enough to hold the baking pan.
Baking Tin should be made of Aluminium.

If baking tin comes into direct contact with the base of the pressure cooker, it can burn (overbake) the cake. So use pressure cooker container which has big holes in it or any aluminum small stand.
No gasket and whistle are needed. Remove them before baking.
Don’t add water to the pressure cooker.

Let it bake for 50 -60 minutes on low flame. After 60 minutes check cake with a knife, if the mixture does not stick, it means the cake is done.
If batter still sticks to knife then again bake for another 10 minutes. Do not open the lid immediately.
Eggless Pressure Cooker Cake is ready.