Preheat the oven to 400. Line two large baking sheets with silicone liners or parchment paper
Beat together the cream cheese and sugar until smooth. Beat in the flour and vanilla, then the egg yolk. Stir in the chocolate chips and set aside.
Unroll one sheet of puff pastry. You want it in a rectangle about 9x13 - so roll it out a little if you need to.
Cut the dough with a pizza cutter of knife - 3 strips the long way, 4 strips the shorter way, for 12 squares per sheet of puff pastry, 24 total.
Divide the squares between the baking sheets.
Add a spoonful of the cream cheese mixture in the center of each square, slightly on the diagonal.
Fold one corner over the filling, swipe the top of the dough and the opposite corner with the egg wash, then pull the opposite corner over the top to seal.
Brush the outside of the pastries with egg wash, then sprinkle with decorating sugar!
Bake the danishes at 400 for 15-18 minutes or until golden brown.
Remove from the oven, let cool a little on the baking tray, then serve!