Preheat the oven to 200 * C.
Put the oil in a microwave dish and pour in the water. Put a bowl of water and butter in the microwave and heat to a boil (2-3 minutes at full power.)
Sift the flour into the water and oil mixture and stir well.
Put in the microwave for another 40 seconds.
Cool slightly and beat in one egg at a time, mixing thoroughly.
Put the dough on a baking sheet covered with parchment.
Bake for 25-30 minutes without opening the oven.
Turn off the oven and leave the finished cakes in it for 3-5 minutes, then get out and cool.
Prepare the cream. Put the mascarpone in a whipping dish and add some of the condensed milk. At low speeds, gently beat the mixer. Add more condensed milk and beat gently again.
Adjust the thickness and sweetness of the cream to your own taste.
If the sweetness of condensed milk is not enough, add powdered sugar.