Cranberry-Apple Tartlets

Ingredients

• 1 tablespoon water
• 1 cup fresh or frozen cranberries
• 1 tablespoon demerara sugar
• 1 package refrigerated piecrust
• 13 teaspoon kosher salt
• pinch ground nutmeg
• 1 teaspoon vanilla extract
• 1 tablespoon cornstarch
• 1 large egg white, lightly beaten
• ½ cup packed light brown sugar
• 1 medium Honeycrisp apple, peeled and finely chopped
• 2 tablespoons unsalted butter