01 - Preheat oven to 350°F. Lightly grease a standard muffin tin or tartlet pans.
02 - Combine crushed pretzels, melted butter, and brown sugar in a mixing bowl. Stir until the mixture resembles wet sand.
03 - Press about 2 tablespoons of the mixture into the base and sides of each muffin cup to create a firm shell. Bake crusts for 8 minutes, then remove from oven and allow to cool slightly.
04 - Warm heavy cream in a small saucepan until steaming but not boiling. Remove from heat, add chopped chocolate, and stir until smooth.
05 - In a separate mixing bowl, whisk together pumpkin puree, granulated sugar, egg, cinnamon, nutmeg, ginger, vanilla extract, and sea salt. Gradually mix in the chocolate-cream blend until smooth and homogeneous.
06 - Divide pumpkin chocolate filling evenly among the prepared crusts.
07 - Bake for 12 minutes, or until the centers are just set. Tartlets will firm up as they cool.
08 - Cool in pan for 15 minutes, then gently remove and transfer to a wire rack to cool completely.
09 - Drizzle with melted chocolate and sprinkle with flaky sea salt, if desired. Chill tartlets at least 20 minutes before serving.