In a large mixing bowl, beat the butter and shortening together using an electric mixer until fluffy—this takes about 2-3 minutes.

Add the packed brown sugar, mixing well before incorporating the eggs and vanilla. Blend until everything is well combined and the mixture is light in color—this should take an additional minute.

In another bowl, whisk together the oats, flour, baking soda, baking powder, cinnamon, and salt.

Gradually add the dry ingredients to the wet mixture in three parts, mixing gently until just combined.

Carefully fold in the toffee bits and cover the bowl with a lid or plastic wrap, refrigerating the dough for 30 minutes.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper or a silicone mat.

Once chilled, use a 1-tablespoon scoop to portion dough onto the prepared baking sheets, spacing them approximately 3 inches apart as they will spread while baking.

Bake in the preheated oven for about 13-15 minutes, until the edges are golden brown—don’t worry if the centers still appear light!

Allow cookies to cool on the baking sheet for 5 minutes before transferring them to a cooling rack.