Beat the egg whites, separated from the yolks, with a mixer on high speed until you get a thick foam.

Mix the egg yolks with sugar and vanilla until fluffy.

Add oil to the egg yolks and mix briefly.

Alternately add flour mixed with baking powder and milk to the egg yolks - mix together on low speed of the mixer - just until combined.

Repeat until all products are used.

Add the egg white foam in two portions and gently mix with a spoon.

Transfer the dough to the prepared baking pan.

Bake the cake in an oven preheated to 170 degrees Celsius (top/bottom mode) for about 50-55 minutes - until a dry stick comes out.

After baking, cool the cake.

Transfer mascarpone cheese, heavy cream, and sugar to a tall bowl.

Mix on high speed with a mixer for several minutes - until you get a thick cream.

Spread part of the jam over the cooled cake.

Spread the mascarpone cream evenly on top.

Spoon jam onto the cream, then swirl it together with the cream to create "swirls".