Defrost puff pastry sheets side by side on a baking tray lined with baking paper for about 10 minutes. In the meantime, heat the oil in a pan. Fry the minced meat crumbly while turning. Season to taste with salt and pepper. Grate the Gouda, remove the pan from the heat and mix the Gouda into the mince.
Roll out puff pastry sheets one after the other on a floured work surface (approx. 23 x 24 cm). Cut out a circle (approx. 20 cm Ø) from each pastry sheet. Spread the chopping mixture over one circle of dough, adding a little more in the middle to create a small rise. Leave about 0.5 cm free at the edge of the dough. Place a second circle of dough on top. Place a glass in the middle. Cut the dough from the edge of the glass into about 16 pieces. Turn each piece so that the cutting edge is facing upwards, press the ends together.
Remove glass. Whisk the egg yolk and milk and brush the dough with it. Sprinkle sesame seeds in the middle. Carefully place the puff pastry cake on a baking tray lined with baking paper and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 20-25 minutes.