Preheat your oven to 325°F. This ensures your cookies bake evenly and achieve that golden-brown finish.
Line two baking sheets with parchment paper and set them aside. This will prevent the cookies from sticking and make cleanup a breeze.
In a food processor, add the hazelnuts and chop them for a few seconds until they’re coarse. You may want to leave some larger pieces for a satisfying crunch.
In a separate bowl, mix the all-purpose flour, baking powder, baking soda, old-fashioned oats, and salt together. This dry mixture is crucial for balanced flavors and the cookie structure.
In the bowl of your mixer, add the unsalted butter, brown sugar, and granulated sugar. Beat on medium speed for about 3 to 5 minutes until the mixture is light and fluffy.
Next, beat in the eggs and vanilla extract for about a minute. This adds moisture and flavor, making your cookie dough irresistible.
Gradually add the dry flour mixture to the butter mixture and stir just until everything is blended. Be careful not to overmix, as this can lead to tough cookies.
Now, stir in the toffee bits, chocolate chips, and the chopped hazelnuts. This is where the magic happens; the dough should look delightful with all those mix-ins.
Using a medium ice cream scoop, scoop the cookie dough and drop it onto the prepared baking sheets, spacing them about 1 inch apart. Don’t flatten the dough; let it rise naturally while baking.
Bake for about 12 minutes or until the edges turn golden. The centers may look slightly underbaked, but they’ll firm up as they cool.
Once baked, cool the cookies on the baking sheets for a couple of minutes, then transfer them to cooling racks to cool completely. This step ensures they’re perfectly chewy!