Mix together rhubarb, strawberries, lemon juice, vanilla, sugar, and cornstarch in a medium saucepan. Heat over medium and simmer, stirring occasionally, until rhubarb is tender, about 7-10 minutes. Set aside and let cool.
Preheat oven to 375° and line two baking sheets with parchment paper. Then whisk together egg and 2 tablespoons of water. Set aside.
Start by working with one sheet of puff pastry while the other sheet remains cool in the refrigerator. Unfold the puff pastry onto a lightly floured sheet of parchment. Using a rolling pin, roll pastry into a 10” square. Cut into 4 even squares.
Place a scant (a little less than) ¼ cup of filling into the center of each square. Brush two adjoining edges of each square with egg wash (see picture). Carefully fold each square in half diagonally to form a triangle (some of the filling may squeeze out). Using a fork, crimp the edges to seal the pastries.
Carefully transfer to prepared baking sheet, spacing at least two inches apart. Brush tops with egg wash and sprinkle with sugar.
Repeat with remaining puff pastry sheet, making a total of 8 turnovers. (If you only have one sheet pan, you can bake the first 4 turnovers while you prepare the last 4).
Bake 18-20 minutes or until golden brown and puffed. Let sit for a few minutes then transfer to a cooling rack.
Make the glaze:
In a large bowl, beat together cream cheese and vanilla using an electric hand mixer until smooth, about 2 minutes. Add milk and powdered sugar, and beat on low until smooth and creamy, about 1-2 minutes. If needed, add more milk to thin out glaze or add more powdered sugar to thicken it up a bit.
Drizzle glaze over cooled turnovers. Enjoy!
When working with puff pastry, you want to be cold (but not frozen), so it’s best to let it thaw in the refrigerator overnight.
You can make the strawberry rhubarb filling the day before and store in the refrigerator. Also, if you have extra filling, it would be amazing on vanilla ice cream!
Turnovers are best eaten the same day, but you can store them in an airtight container in the refrigerator for up to three days.
Recipe by Modern Farmhouse Eats at http://www.modernfarmhouseeats.com/strawberry-rhubarb-turnovers-with-cream-cheese-glaze/