Cook the Filling: In a small saucepan, combine dark brown sugar, cream, egg, vanilla extract, salt, and pecans. Cook over medium heat while stirring continuously until bubbling and thickened (about 5 minutes). Transfer to a bowl, cool, and refrigerate until chilled. Stir in corn syrup before using.

Preheat the Oven: Set your oven to 175°C (350°F). Line a standard 12-cup muffin pan with paper liners to prepare for the batter.

Mix the Batter: In a large bowl, whisk together pumpkin puree, granulated sugar, dark brown sugar, eggs, vegetable oil, and vanilla until the mixture is smooth. Add baking powder, baking soda, pumpkin pie spice, and salt, then incorporate flour gently. Lastly, add the milk and whisk until the batter is smooth.

Bake the Cupcakes: Evenly distribute the batter among the prepared liners. Bake for 16-20 minutes until the surface feels firm and a skewer inserted in the center comes out clean. Cool completely on a wire rack once baked.

Make the Frosting: In a large bowl, beat softened butter with maple syrup using an electric mixer until light and creamy. Gradually add powdered sugar in thirds, beating well each time. Then blend in vanilla extract, cinnamon, and half of the cream until fluffy. Mix in the remaining cream and the last third of powdered sugar, beating until the frosting is fluffy and pale.

Fill the Cupcakes: With a small paring knife, cut a circular section from the center of each cupcake, about 2 cm deep, to create wells. Fill each well with approximately 1 teaspoon of the chilled pecan filling.

Frost and Decorate: Spread the salted maple cinnamon frosting generously over each filled cupcake. Trim the bases of the cupcake cores to form flat tops. Melt chocolate chips and use as 'glue' to attach mini chocolate chips to mimic pumpkin stems, placing them gently on top of each frosted cupcake to garnish.