
Preheat the oven to 350℉. Lightly 2 sheet pans with parchment paper.
Combine the soft butter and sugar in a large bowl and stir until creamy and well combined. Add the egg yolks and vanilla and stir again.
Add the baking soda and baking powder and stir until incorporated then add the flour. Stir until all of the flour has been combined and the dough starts to clump.
Add the toffee bits and stir until incorporated and no loose bits are at the bottom of the bowl.
Scoop up the dough with a 1½-2 tablespoon ice cream scooper into mounds spaced 2 inches apart on the prepared sheet pans. (This dough will be a little crumbly. It's supposed to be that way. When you scoop it up to form the cookies, pack the dough into the scooper tightly pushing against the sides of the bowl and scraping any excess off at the top of the bowl.
Bake for 12-16 minutes or until lightly golden brown. Remove from the oven and sprinkle lightly with sugar, if desired. Allow to sit on the pan for 4-5 minutes, then transfer to a cooling rack to cool completely.