Thaw puff pastry according to package instructions.

Meanwhile, heat a large skillet over medium-high heat. Once hot, drop in sliced onions, and cook, stirring occasionally, until dark brown and somewhat soft (about 5 minutes). Reduce heat to medium, and add the butter and a big pinch of kosher salt, stirring to coat the onions. Continue to cook, stirring frequently, until the onions are soft and sweet (5 to 10 minutes more). Add 3 tablespoons of wine, and using a wooden spoon, scrape up the brown bits off the bottom of the pan. Continue to cook for just 1 minute more until most of the liquid has evaporated. Season to taste with kosher salt and black pepper, then transfer onions to a cutting board to cool.

Once cool, chop up caramelized onions, then add to a medium bowl along with the Cambozola, 3 tablespoons heavy cream, diced pear and chopped parsley. Using a fork, mash together the ingredients until combined. Season to taste with kosher salt and black pepper, then stir in the beaten egg.

Preheat an oven to 400°F, and place an oven rack in the middle position. Lightly grease a 12 cup muffin tin with nonstick cooking spray.

Roll out puff pastry into a 12-inch square. Cut pastry into 9 even squares, then place a square in each muffin cup, pressing into the bottom and up the sides and leaving the corners pointing up. Repeat with remaining sheet of puff pastry, but only cut 3 additional squares. Divide filling between the cups. Fold pastry over filling, pressing corners together to meet in center. Beat egg yolk and 1 tablespoon of heavy cream together, then brush the top of each pastry evenly with the egg wash. Bake until pastry is golden brown and puffed (about 25 minutes).

Transfer the muffin tin to a cooling rack, and let the puffs cool in the tin for 10 minutes. Turn out the puffs onto the cooling rack, and let cool slightly before serving. Enjoy with a glass of red Bordeaux wine!