In a small saucepan, melt 2 tablespoons of unsalted butter over low heat. Add corn syrup, brown sugar, cornstarch, 0.25 teaspoon salt, and the lightly beaten egg. Whisk until smooth.

Increase heat to medium and cook, stirring constantly, until the mixture begins to boil and thicken. Remove from heat.

Stir in the chopped toasted pecans and 0.5 teaspoon vanilla extract. Let cool for 10 minutes, then refrigerate for at least one hour or until thickened.

Preheat oven to 350°F (175°C). Line a 12-cup muffin pan with paper liners.

In a small bowl, whisk together 0.25 teaspoon salt, baking powder, and all-purpose flour. Set aside.

In a large bowl, combine melted butter, packed brown sugar, and granulated sugar. Mix on medium speed for about 1 minute until well combined.

Beat in the 2 large eggs, one at a time, mixing well after each addition.

Add buttermilk and the dry flour mixture in 3 additions, alternating between the two. Mix just until combined after each addition, being careful not to overmix.

Fill cupcake liners about two-thirds full with batter. Bake for 14-17 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Cool completely on a wire rack before filling and frosting.

In a large bowl or stand mixer, beat the softened unsalted butter until smooth.

Add 3 tablespoons packed brown sugar and cream together until fluffy, about 2-3 minutes. This helps the brown sugar dissolve.

Stir in heavy whipping cream, 1 teaspoon vanilla extract, and 0.25 teaspoon salt until combined.

Reduce mixer speed to medium-low. Slowly add the powdered sugar, mixing until smooth, about 1-2 minutes. Increase mixer speed to medium-high and beat until fluffy and light, about 5 minutes.

If not using immediately, store frosting in an airtight container in the refrigerator for up to 2 days. Let it come to room temperature and re-fluff with the mixer before using.

Once cupcakes are completely cool, use a small knife or cupcake corer to scoop out the center of each cupcake, creating a cavity.

Fill each cupcake cavity with approximately 1 tablespoon of the chilled pecan pie filling.

Frost the cupcakes as desired (a Wilton 1M open star tip works well for a decorative swirl).

Garnish each cupcake with a toasted pecan half.

Store finished cupcakes in an airtight container in the refrigerator for up to 3 days. Cupcakes can be frozen before frosting.