Cube the ½ cup of butter and place it into a saucepan. Turn the heat to medium-high and allow the butter to melt, stirring occasionally. Once melted, it will begin to bubble, foam, and brown. When the butter is an amber colour, pour it into a large heatproof bowl, scraping all the brown bits with it. This whole process should take 5-10 minutes. Allow the butter to cool for at least 10 minutes.
Lower the heat to medium and add the pecan pieces to the pot with 2 tablespoon fresh butter and 2 tablespoon white sugar. Stir and toast for 5 minutes until the sugar has dissolved. Watch to ensure they don't burn. Remove to a bowl.
To the large bowl with the brown butter, add the brown sugar and remaining 2 tablespoon white sugar, then whisk until smooth. Add the maple syrup, vanilla, egg, and egg yolk. Whisk.
Add the flour, cornstarch, baking soda, cinnamon, and salt. Fold with a spatula just until combined. Then fold in the toasted pecans and mini chocolate chips, reserving some for topping the cookies.
Cover the bowl and chill the cookie dough for 2 hours, or overnight.
When ready to bake, preheat the oven to 350ºF and prepare a large baking sheet with parchment paper.
Scoop the dough into 2 tablespoon size balls with a cookie scoop. Press extra chopped pecans into the tops of the cookies then roll in granulated sugar.
Bake for 11-14 minutes. The edges will be set and the middles still soft. Cool on the baking sheet for 15 minutes then transfer to a wire rack to cool completely. Enjoy!