Preheat oven to 350F. Line 2 baking sheets with parchment paper.

Whisk together flour, oats, baking soda, and salt to remove any clumps. Set aside.

In the bowl of a stand mixer fitted with a paddle attachment, cream together the brown sugar and butter until light and fluffy. Beat in vanilla and egg. Add in the flour mixture and beat until just combined. Use a rubber spatula to fold in the toffee bits.

Drop dough by tablespoonfuls onto the prepared baking sheets. Bake for 11 minutes. Let cool on sheet for a minute or 2 before transferring to a wire rack to cool completely.