Preheat oven to 350°F (175°C). Grease a standard 12-cup muffin tin thoroughly with butter or nonstick baking spray, or line with silicone baking cups or tulip liners.

In a large mixing bowl, whisk together the dark brown sugar, all-purpose flour, finely chopped pecans, and sea salt until thoroughly combined and free of lumps.

In a separate measuring pitcher, whisk together the melted butter, room temperature eggs, and pure vanilla extract until smooth.

Pour the wet egg-butter mixture into the dry pecan mixture. Gently fold with a rubber spatula or wooden spoon just until incorporated. Do not overmix.

Divide the batter evenly among the 12 muffin cups, filling each approximately 2/3 full. Press one whole pecan half gently onto the center of each muffin top.

Bake at 350°F for 18 to 20 minutes until the edges are golden and lightly crisp, and the centers are set but slightly soft to the touch (do not overbake, or they will lose their signature gooey pecan pie texture).

Remove from oven and allow muffins to cool in the pan for 8 to 10 minutes. Run a thin butter knife gently around the edges to release, transfer to a wire cooling rack, and enjoy warm.