Heat oven to 350℉/177℃.
Line a muffin tin with paper baking cups or spray with baking spray. Set aside.
Pour 1 cup pecans onto sheet pan.
Bake until hot all the way through and just starting to brown, about 5-6 minutes.
Once cool, chop pecans. Set aside.
In a small bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
With an electric mixer, beat butter and sugar until light and fluffy, about 2-3 minutes.
Add egg, egg yolk, and vanilla.
Beat until fully combined.
Add flour mixture alternately with milk, beginning and ending with flour mixture.
Stir in 1 cup toasted, chopped pecans.
Fill muffin cup ¾ full.
Top each with roughly chopped pecans.
Bake for 20 minutes, or until done.