Remove the puff pastry from the fridge about 5 minutes before. Preheat the oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Line baking tray with baking paper. Cut ham slices in half.
Roll out the puff pastry, cut into 6 rectangles and place on the baking tray. Cover each with 1⁄2 slice of ham and 1 slice of pineapple. Whip dough corners to the middle. Whisk egg yolk and milk, brush dough with it.
Sprinkle with cheese. Bake in a hot oven for 10-15 minutes. Sprinkle with cress. Taste also cold.