Take the 5-liter pressure cooker and put 11/2 cup salt inside the pressure cooker and spread it evenly. Now put a wired rack or any stand or container over the salt and let the salt heated for 10 minutes on medium flame by covering the lid. Meanwhile, let’s prepare the batter.
In a mixing bowl put all purpose flour, powdered sugar, baking soda, baking powder and sieve it. Mix it well and keep aside the sifted dry ingredients.
Now in another bowl mix, all the wet ingredients condense milk, water, and vanilla essence.
Now put dry ingredients into the bowl of wet ingredients and mix it well till no lumps.
Now add melted butter, oil and mix it well in cut and fold method till all the oil gets absorbed.
Lastly, add vinegar and mix it well.
To make marble cake we have to make the chocolate batter and vanilla batter so for that Keep more than half batter vanilla and mix cocoa powder in rest of the batter (add little water to adjust the consistency )and mix it well
Fill both the batter separately in a piping bag.
Grease and dust the tin with all purpose flour.
Now pour vanilla batter into the greased tin and spread with help of a spoon to make the base.
Now spread chocolate batter and then vanilla batter and with the help of toothpick make a swirl.
You may pour the vanilla and chocolate batters in the pan in an alternate sequence or the sequence of your desire, maybe chocolate first and vanilla later. However, you want to do it.
After pouring both the batters tab the cake pan so that air bubbles get removed.
Now put cake tin inside the heated pressure cooker onto the stand, cover the lid and remove the whistles and bake it on medium-high flame for 35-40 minutes or till cake gets fully baked.
Once baked, take out the cake tin from the pressure cooker and let it cool down for sometime before inverting.
Once cool, run a butter knife all around the edges and invert the cake onto plate.
Cut into slices when gets cool down completely. If you cut the hot cake into slices then it will get the break.