Place puff pastry sheets next to each other and allow to thaw. Coarsely grate the Comté. Season ricotta with salt and pepper. Wash basil, shake dry, pluck leaves and chop coarsely.
Preheat oven (electric cooker: 225 °C/circulating air: 200 °C/gas: see manufacturer). Line two trays with baking paper. Spread the ricotta on the dough plates and spread. Cover each with bresaola, sprinkle with basil and Comté.
Roll up the plates from the short side and cut them into approx. 8 slices each. Place on the plates.
Whisk the egg yolk and milk, spread a thin layer on the snails. Bake one after the other in a hot oven for about 15 minutes. Taste warm and cold.