Prepare the Dough:
If using homemade rough puff pastry, do the second refrigeration step then continue. If you’re using store-bought frozen puff pastry, make sure it’s completely thawed. Store the dough in the refrigerator until you need it.
Make the Cranberry Sauce:
Rinse the cranberries, reserving 1/4 cup (25g) for some added texture in the finished tarts. In a medium saucepan, combine the leftover cranberries, water, orange juice and sugar. Stir the mixture occasionally while it comes to a simmer. When it reaches a simmer, lower the heat to medium-low, and cook, stirring occasionally, until the liquid has reduced and the cranberries have burst, about 10 minutes. Off the heat, stir in the reserved cranberries, orange zest and vanilla extract. Allow the sauce to cool slightly while you make the pastry.
Preheat and prep the muffin pan:
Step 1: Preheat the oven to 400°F (204°C). Coat a 12-cup muffin tin in nonstick spray or butter.
Roll and Cut the Puff Pastry:
晃晃撥皮工作-擀開成四分之一英寸厚的12×16吋長方形 If using 2 sheets of store-bought puff pastry, overlap the edge of one sheet with the other and roll with a pin to join the 2 sheets. Cut the dough into 12 squares, each 4 inches or so across.
Assemble the Tarts:
Brush the egg wash all over the puff pastry squares, including the edges. Place each square in a muffin cup and press gently to create a “crust.” Divide the brie into 12 slices, each about 1/2 ounce (14g), placing one in the center of each pastry. Top each piece of brie with 2 heaping teaspoons of cranberry sauce. Gently fold the corners of the pastry in toward the center, forming a rustic tart shape. Scatter coarse sugar over each tart.
Bake the Tarts:
Bake for about 20 minutes, or until the pastry is golden brown. For pecans, if using, add them halfway through the baking time, pressing one or two halves into the center of each tart, and baking for the last 10 minutes.
Garnish and Serve:
When baked, take out the tarts from the oven and finish with some flaky sea salt and fresh thyme leaves. Allow the tarts to cool for a few minutes, then gently remove them from the muffin pan with a spoon. Serve warm.
Storing Leftovers:
Leftover tarts will keep well in the fridge for up to 3 days. To reheat them, cover them with aluminum foil and bake them in a 300°F (149°C) oven for a few minutes until heated through.