Preheat the oven to 400 degrees. Line 2 sheet pans with parchment paper.
Place the cream cheese and sugar in the bowl of an electric mixer fitted with a paddle attachment and cream them together on low speed until smooth. With the mixer still on low, add the egg yolks, ricotta, vanilla, salt, and mix until just combined. Don’t whip!
Lightly flour a rolling pin and your working surface. Unfold one sheet of puff pastry and gently roll it out until it is a 10 x 10 inch square. Cut the sheet into 9 squares. Place squares on one sheet pan. Create an inner square on the inside of each square by lightly pressing a knife about 1/2 inch from the edge. Repeat with second sheet of puff pastry.
Place one heaping teaspoon of cream cheese into the center of each square. Put one strawberry half in the center of cream cheese within each pastry, cut side down. Note: if not putting strawberry, add 1/2 teaspoon of more cream cheese filling.
Brush the edges of each filled pastry with the egg wash. Place the sheet pans in the refrigerator for 15 minutes.
Bake the pastries for about 15 minutes until golden brown, rotating the pans half-way through.
Optional step: If you want to add an extra flair to the Danish, you can coat the filling with glaze. To do so, you must wait until the Danish is completely cool. Once they've cooled, place about 1/2 cup of apple jelly into a microwave-safe bowl and microwave in 30-second increments until liquefied. Brush the jelly over the strawberry and cream cheese filling until it's completely covered in a thin layer of jelly. Let it sit for a couple minutes and then serve.
Pastries are best served immediately or same day. May get soggy if stored past 24 hours.