For the recipe you will need:
butter – 50g
water – 1 glass
flour – 1 cup
baking powder – 1 tsp
sugar (fine) – 1/4 cup
egg – 4 pcs.
lemon (grated zest) – 1 tsp
vegetable oil for frying
for citrus syrup:

lemon juice – 1/2 cup
water – 1/2 cup
sugar (fine) – 1 cup
oranges – 2 pcs.
lemons – 2 pcs.
To prepare Custard Donuts with Citrus Syrup, you need:

To prepare the citrus syrup, combine lemon juice, water, sugar, orange and lemon zest and cook over high heat, stirring until sugar dissolves. Then reduce the heat and continue to cook the syrup, stirring, for another 6-8 minutes, until it thickens a little. Remove syrup from stove and let cool.

Boil water, add butter and stir. Pour the sifted flour mixed with baking powder and sugar into the water with butter. Knead into a smooth shiny dough. Reduce heat to low and cook, stirring, until the mixture begins to pull away from the sides of the pan. Remove the dish with the dough from the fire.

Transfer the dough to the bowl of the mixer, add one egg at a time, each time kneading the dough with a mixer until smooth. Add lemon zest.

Put the dough with a teaspoon into boiling oil and fry the donuts for 4-5 minutes until golden brown. Transfer hot donuts to paper towels to absorb excess oil.

Serve citrus syrup with ready-made donuts.