Step 1

For jam: In a large, nonreactive bowl, thoroughly combine rhubarb, raspberries, sugar, lemon juice, cinnamon and salt. Refrigerate, covered, at least 6 hours or overnight.

Step 2

In a 4- to 5-quart heavy pot, bring fruit mixture to a boil over medium heat, stirring often. Let boil until thickened, 10 to 12 minutes. Remove from heat; stir in rosewater, if using, and the vanilla. Let cool. (You’ll make about 2 cups of jam and only use 1/2 cup for the Danish. Refrigerate extra up to 3 weeks or freeze up to 1 year.)

Step 3

Position oven racks in the upper and lower thirds of oven. Preheat oven to 400°.

Step 4

For filling: In a large bowl, beat cream cheese, sugar, egg yolk and vanilla with a mixer on medium until smooth. Set aside.

Step 5

For Danish: Line two baking sheets with parchment paper. Unfold pastry sheets on a lightly flour surface. Use a knife or pizza wheel to cut each pastry sheet into quarters.

Step 6

Working with one square at a time, fold about 1 1/2 inches of all four corners in toward center, pressing corners firmly. Evenly space pastries on prepared baking sheets. Spoon about 2 tablespoons cream cheese filling into center of each pastry. Use the back of a spoon to spread filling slightly and create a deep divot in the center for the jam so it doesn’t run during baking. Spoon about 1 tablespoon jam on top of filling.

Step 7

For egg wash, in a small cup, whisk together egg, the water and salt. Use a pastry brush to lightly brush any exposed pastry with egg wash. Sprinkle the egg-washed areas with turbinado sugar.

Step 8

Bake until puffed and dark golden brown, rotating baking sheets halfway through the baking time, 25 to 30 minutes. Let cool on baking sheets at least 30 minutes before serving.