Preheat your oven to 350°F and grease your muffin pan with nonstick cooking spray. In a small bowl, mix together the sugar and cinnamon, then set it aside.
Lightly flour your work surface, then place one sheet of crescent dough on top. Roll the dough with a rolling pin if needed, making a 14 x 8-inch rectangle.
Starting from the long end of the rectangle, roll the edges of the dough to form a large log. Use a sharp knife to cut the log in half, then cut the shorter logs in half lengthwise. You should have 4 smaller logs per sheet of dough.
Repeat with the second layer of dough. Roll each small log with the layers of dough facing up, to form a ball of dough with a muffin shape. Tuck the end of the dough underneath each cruffin.
Place each cruffin dough in the prepared muffin tin, layered side up, and bake for 20-25 minutes until they turn a deep golden brown and are fully cooked.
Remember to do this while they're hot out of the oven, still coated with melted butter, or the cinnamon sugar won't stick. Exercise caution to avoid burning yourself!