In a saucepan over medium heat, combine the butter, sugar, and cinnamon. Add the chopped apples.
Allow to simmer for 10 minutes or until the apples are softened.
Dissolve the cornstarch in the water in a small bowl.
Add the cornstarch slurry to the saucepan and continue to simmer for 2-3 minutes.
Remove from the heat and allow to cool slightly.
Melt the butter in a small bowl.
Add the brown sugar, flour, and cinnamon.
Stir to a crumbly streusel.
Preheat the oven to 400℉.
Remove one puff pastry sheet from the refrigerator.
Slice the sheet into 12 equal strips.
Pinch 2 strips together and twist the strip like an old school telephone cord.
Wrap the twisted strip into a circle form and pinch the end to stick to the pastry dough.
Make a small well in the center by lightly pushing down the dough.
After the first 6 are twisted and wrapped, fill the center of the pastry with apple filling.
Sprinkle streusel on top of the filling.
Place the prepared danishes in the refrigerator while making the second pan using the instructions above.
When both pans are ready, bake for 18-20 minutes, or until the pastry and streusel begin to brown.
Remove to a cooling rack and allow to cool while preparing the icing.
In a small bowl, stir the powdered sugar and heavy cream until smooth.
Drizzle the icing onto the cooled Danishes and serve.