Peel onions and garlic, dice onions, chop garlic finely. Heat oil in a pan, fry onions and garlic for about 3 minutes. Cover the bottom of a springform pan (24 cm Ø) with baking paper.
Coat the mould edge with oil.
Cut the ham into short strips. Wash parsley, shake dry, pluck leaves and chop roughly. Mix ham, parsley and Gouda with the steamed ingredients and season with a little pepper.
Unroll the dough on the baking paper. Cut dough and paper lengthwise into 3 strips. Spread the topping evenly on the dough. Loosely roll up each strip without paper lengthwise. Place the strips in like a snail, starting at the edge and moving towards the middle.
Pull the strips slightly apart so that the whole mould is laid out. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 20 minutes.