In a large mixing bowl, cream together butter and brown sugar until light and fluffy, about 2-3 minutes. Add egg and vanilla extract, blending until smooth.

In a separate bowl, whisk together flour, baking powder, and salt, then gradually mix this dry blend into the butter mixture until just combined.

Shape the cookie dough into 1¼-inch balls and place on a lined baking sheet. Press your thumb into the center of each ball to create an indentation for the filling. Chill in refrigerator for 20 minutes.

Preheat your oven to 350°F (175°C) while the cookie dough chills.

Mix together chopped pecans, brown sugar, heavy cream, and vanilla extract until well-combined. Fill each cookie indentation with the pecan mixture.

Bake cookies for 8-12 minutes until golden and set around the edges. Let cool on baking sheets before transferring to a wire rack.

To create the bourbon glaze, whisk together powdered sugar, bourbon, and heavy cream until smooth. Drizzle over the cooled cookies and sprinkle with sea salt.

Serve with a glass of cold milk or warm coffee. Store leftovers in an airtight container.