Cream the softened unsalted butter, granulated sugar, and brown sugar together using an electric mixer until light and fluffy.

Add the vanilla extract and mix on low speed until fully integrated.

In a separate bowl, whisk together the all-purpose flour and baking soda, then gradually blend this dry mixture into the butter mixture.

Fold in the toffee bits (and optional chopped nuts) gently with a spatula.

Divide the dough into two logs, wrap tightly in plastic wrap, and refrigerate for at least 4 hours.

Preheat the oven to 350°F (175°C), slice the chilled dough into ¼-inch thick cookies, and arrange on parchment-lined baking sheets.

Bake for 10-12 minutes until edges are golden, and allow them to cool slightly before transferring to wire racks.