Preheat the oven 400°. to In a large mixing bowl, mix the cream cheese, 1 egg, granulated sugar, and the salt until creamy. Set aside.
Lay the thawed puff pastry dough out on a parchment lined 9x13 cookie sheet. Roll the puff pastry out with a pastry roller until the dough creases smooth out.
Starting from the inner seam where the dough was folded in half, cut 12, ½ inch strips on each side of the pastry dough going out to the end of the dough.
Spread the cheese mixture over the center of the dough. Place the rhubarb sauce over the top of the cheese mixture.
Shape the danish by folding the top two strips of dough over top of filling and start to braid the dough by bringing the strip from the left over to the right, then the strip from the right over to the left. Tuck into the danish to seal.
Continue with the braid until the the last two strips at the bottom. Bring the bottom two strips up towards the filling and and fold them over top of the danish. Then, bring the last two strips across each other and pinch slightly to seal.
Whisk the remaining egg until well combined. Brush the danish evenly with the egg. Bake in the oven for 30 minutes, or until the danish is golden brown.
Remove the danish from oven and let cool at 10 minutes before serving. Store leftovers in a covered container.