📖 Instructions

1. Get Started: Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper, this'll stop the cookies from sticking and makes cleanup a breeze. Trust me, you'll thank me later!
2. Grind Hazelnuts: If you're starting with whole hazelnuts, grind them in a food processor until you get a fine flour. Be careful not to over-process; otherwise, you'll end up with hazelnut butter instead of flour. (Although, hazelnut butter cookies sound pretty amazing too, right?)
3. Cream Butter and Sugar: In a large mixing bowl, cream together the softened butter and both sugars (granulated and brown) until the mixture is light and fluffy. This usually takes about 3-5 minutes with an electric mixer. This step is super important because it incorporates air into the dough, which gives the cookies a nice, tender crumb. Don't skimp on this step!
4. Add Egg and Vanilla: Beat in the egg and vanilla extract until well combined. Make sure to scrape down the sides of the bowl to ensure everything is mixed evenly. I like to use a good quality vanilla extract; it really makes a difference in the flavor.
5. Combine Dry Ingredients: In a separate bowl, whisk together the hazelnut flour, all-purpose flour, baking soda, and salt. Whisking ensures that the baking soda and salt are evenly distributed throughout the flour.
6. Mix Wet and Dry Ingredients: Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix, it will make the cookies tough. The dough should be soft and slightly sticky. If it's too sticky to handle, refrigerate it for 30 minutes to make it easier to scoop.
7. Swirl in Nutella: Drop rounded tablespoons of cookie dough onto the prepared baking sheets, leaving some space between each cookie. Using a small spoon or knife, make a well in the center of each cookie and fill it with about a teaspoon of Nutella. Then, swirl the Nutella into the dough using the tip of the spoon or knife. Get creative with your swirls!
8. Bake: Bake for 10-12 minutes, or until the edges are golden brown and the centers are set. Keep a close eye on them, as hazelnut flour can burn easily. Nobody wants burnt cookies, that's a bummer!
9. Cool and Enjoy: Let the cookies cool on the baking sheets for a few minutes before transferring them to a wire rack to cool completely. This prevents them from breaking apart. Once they're cool, grab a glass of milk (or a cup of coffee) and enjoy. You deserve it!