Preheat oven to 220 degrees. Lightly grease a baking sheet (or two). Combine oil and 1 1/3 cups of water in a saucepan. Bring to a boil. Remove from heat. Add flour, stirring vigorously with a wooden spoon. Beat in eggs one at a time (stir well after each egg).
Spoon the balls of dough (12-15 pcs.) On a baking sheet, at a sufficient distance from each other. Bake for 10-15 minutes (for the cakes to rise well), reduce the temperature to 190 degrees and leave in the oven for another 20 minutes. Remove the profiteroles from the oven. Cut from the side with a knife (make a small cut) to release steam from the inside. Return the cakes to the oven for 2-3 minutes. Cool the profiteroles completely on a wire rack.
Combine all the ingredients for the chocolate sauce in a saucepan. Put on low heat and stir the mixture until the chocolate melts. To make a cream, combine the cream, zest, liqueur and beat well with a mixer. Fill the profiteroles with whipped cream using a pastry syringe. Pour the chocolate sauce over the cakes.
Cream-filled profiteroles can be wrapped in foil and frozen. You can also freeze cooked chocolate sauce by cooling it down and transferring it to a plastic container. Defrost food in the refrigerator (then reheat the chocolate sauce over low heat).