Sift flour into bowl and make a well in the middle. Add yeast and 1 tablespoon of the vanilla sugar. Pour in lukewarm milk and stir gently. Cover with towel and set aside for 15 minutes in a warm area.

Add rest of the sugar, melted butter, zest and pinch of salt. Stir, or mix, until no dry flour is left but dough is still tacky. Cover with towel and set aside for 30 minutes in a warm area.

Gently roll out dough on a floured surface until about half an inch thick. Cut out round shapes with cookie cutter or the rim of a small drinking glass. Set dough rounds on a floured surface, cover with towel and let rest them.

Heat 2" of oil to 350F degrees in a heavy bottom pot or pan with lid. Gently place 4 - 5 dough rounds in hot oil and cover. Fry for about 1 - 2 minutes or until golden brown on one side. Flip over only once to fry other side. Place on paper towels to absorb the extra oil.

When doughnuts have cooled, pipe in the jam of your choice. You can poke a hole with a skewer, chopstick or small pairing knife to make it easier.

Finish doughnuts with powdered or granulated sugar.

Best eaten fresh!