Preheat oven to 175°C (350°F).
Grease a 12-cup muffin tin or line with paper liners.
In a medium bowl, stir together chopped pecans, brown sugar, flour, and salt.
In a separate bowl, whisk eggs, melted butter, and vanilla until smooth.
Stir wet mixture into dry ingredients until just combined (do not overmix).
Divide batter evenly among muffin cups (about ¾ full).
Bake for 18–22 minutes, until tops are set and slightly cracked.
Let muffins cool in the pan for 5 minutes, then transfer to a wire rack.
Serve warm or at room temperature.
