Sift flour, sugar, and salt into a medium bowl.

Using a pastry cutter or two butter knives, cut in butter until butter is about the size of Lima beans (peas are too small!)

In a small bowl, whisk egg and cream together. Slowly add to flour and butter mixture, using a fork to combine.

Turn dough out on to a work surface and knead gently just until it comes together. Cut dough in two equal pieces and shape each into a rectangle. Wrap in plastic and refrigerate for at least 1/2 hour and up to 2 days.

Whisk the sugar, flour, and cinnamon together in a small bowl. Set aside.

Line a baking sheet with parchment paper. Set aside.

Remove pastry dough from the fridge and place on a lightly floured surface. (If it's very cold, let it warm just until workable.) Roll out one half of dough into a 12-inch x 8-inch rectangle, 1/8" thick. Trim edges with a pasta or pizza cutting wheel. Cut rectangle in half lengthwise and into quarters crosswise to make 8 equal pieces - 3-inches by 4-inches each. Transfer rectangles to prepared baking sheet.

Repeat rolling and cutting second half of dough.

Brush pastry on baking sheet all over with beaten egg. Scoop 1 heaping tablespoon of filling in the center of 8 dough rectangles, leaving 1/4 inch of bare dough around the edge. Place a second sheet of dough over each rectangle.

Use your fingers to press and seal dough edges. Then press the tines of a fork all around the edges to seal completely.

Prick the top of each pastry several times with a fork or toothpick.

Place pastries on the baking sheet in to the refrigerator while you preheat oven to 350 degrees Fahrenheit. (no need to cover them)

When oven is hot and pastries are cold, transfer baking sheet to oven and bake for 25 to 35 minutes, until flaky and light golden brown. Serve warm.