Put the frozen raspberries, sugar, and cornstarch into a bowl and mix well to combine.
Transfer the filling on top of the dough rectangle leaving 1-2cm around the edge of the dough. Spread the filling out as best you can.
With the longest side facing you, tightly roll the rectangle of dough into a long sausage shape. Pinch the seam with your fingers then cut the sausage of dough in half to make it easier to divide.
Use a very sharp knife or dough cutter to cut each half of the dough into 6 equal sections.
Grease a 9”x13” baking dish with 1 tablespoon melted butter. Arrange the rolls in the dish leaving a little space in-between each one.
Cover with cling wrap and put somewhere warm to rise for 45-60 minutes.
Preheat the oven to 350ºF.
When the raspberry sweet rolls have puffed up, remove the cling wrap and cover the dish with foil. Bake for 25 minutes, then check on the rolls.
If they are not golden in color, remove the foil and bake for a further 5-10 minutes or until golden.
Remove from the oven and set aside.
Make the glaze: Put the powdered sugar, lemon juice, and heavy cream into a bowl. Mix until smooth and adjust consistency as desired.
Drizzle the glaze over the Raspberry Sweet Rolls while they are still warm in the dish.
Serve immediately.