Preheat the Oven: Set your oven to 350°F (175°C). Line a baking sheet with parchment paper and set aside.
Cream the Butter and Sugars: In a large mixing bowl, combine the softened butter with the brown and granulated sugars. Mix until smooth and fluffy.
Add Egg and Vanilla: Add the egg and vanilla extract to the butter-sugar mixture, then continue mixing for about 3 minutes until light and fluffy.
Combine Dry Ingredients: Add the flour, oats, cinnamon, baking soda, and salt to the mixture. Stir just until the dry ingredients are incorporated.
Fold in the Chips and Toffee: Gently fold in the chocolate chips, peanut butter chips, and toffee bits.
Scoop the Dough: Using a large cookie scoop, portion out 10 equally sized cookie dough balls onto the prepared baking sheet.
Bake: Place the baking sheet in the preheated oven and bake for 11-12 minutes. The cookies are ready when the edges start to brown but the centers are still slightly soft.
Cool and Enjoy: Let the cookies cool on the baking sheet for 5-10 minutes before transferring them to a cooling rack. Sprinkle a little sea salt on top while they cool for an added touch of flavor.