In a bowl, whisk together dry ingredients: flour, baking soda, cornstarch, and salt.

In a mixing bowl, beat together melted butter and sugars until completely combined. Add whole egg, egg yolk, and vanilla. Beat until blended.

Slowly add dry ingredients into wet ingredients, beating in between additions.

Fold in candy and chocolate chips.

Transfer to waxed paper or plastic wrap and roll tightly. Refrigerate for 2 hours to overnight.

When ready to bake, preheat oven to 325 degrees.

Line a baking sheet with parchment paper unless you are using a baking stone (as pictured). Scoop dough into 1 to 2 tablespoon increments, depending on the size cookie you desire. Space cookies at least 1 inch apart.

Bake cookies for about 11 minutes or until the edges are set and lightly brown. Remove from oven while still soft and allow to rest on the baking sheet for 7 to 10 minutes before transferring to a cooling rack.

Once cool, transfer to an airtight container and save up to 1 week.