2 cups all-purpose flour, spooned and leveled
1 1/2 cups old-fashioned rolled oats (not quick-cooking)
1/2 teaspoon baking soda
1/2 teaspoon kosher salt
1 cup (2 sticks) unsalted butter, at room temperature
1 cup packed light brown sugar
1/2 cup granulated sugar
2 large eggs
2 teaspoons pure vanilla extract
4 1.4-ounce chocolate-covered toffee candy bars (such as Heath or Skor bars), finely chopped
1 cup semisweet chocolate chips
Heat oven to 375° F. Line 2 large baking sheets with parchment.
In a medium bowl, mix together the flour, oats, baking soda, and salt.
In another bowl, beat together the butter and sugars using an electric mixer on medium-high speed until creamy, 2 to 3 minutes. Beat in the eggs, one at a time, then beat in the vanilla.
Reduce the mixer speed to low and gradually add the flour mixture, mixing just until combined (do not overmix). Fold in the toffee pieces and chocolate chips.
Drop tablespoonfuls of the dough onto baking sheets, spacing them 2 inches apart. Bake until golden, about 8 minutes. Let cool slightly in the pans, then transfer to a wire rack to cool completely.
Store the cookies at room temperature in an airtight container for up to 5 days.