Heat the oil in a heavy-based pot until it reaches 355F (180C). Get a plate lined with paper towels ready for draining.
Add the eggs, ricotta, orange zest and juice to a mixing bowl and whisk until smooth.
Combine all the dry ingredients in a separate bowl (flour, sugar, salt, and baking powder) then add to the wet ingredients. Fold everything together to form a smooth and sticky dough.
Use a tablespoon to drop the dough into the hot oil (do this in batches about 3-4 doughnuts at a time). Fry each doughnut for 5 minutes until a deep golden brown then drain on kitchen paper.
Once cooled, dusted with powdered sugar and serve.