Instructions:
- In a food processor, pulse the rolled oats until they resemble a fine flour. In a medium bowl, whisk together the ground oats, all-purpose flour, baking soda, and salt. Set aside.
- In the bowl of a stand mixer, beat the softened butter, granulated sugar, and brown sugar on medium speed until light and fluffy (about 3 minutes). Scrape down the sides well.
- Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Mix in the vanilla extract.
- Gradually add the dry ingredient mixture to the wet mixture on low speed until just combined. Do not overmix!
- Gently fold in the ground almonds, semisweet chocolate chips, milk chocolate chips (if using), and any optional chopped nuts until evenly distributed.
- Cover the bowl tightly with plastic wrap and refrigerate for a minimum of 2 hours, ideally overnight. This chilling step is crucial for texture.
- Preheat oven to 375°F (190°C). Line baking sheets with parchment paper or silicone mats.
- Scoop rounded tablespoons of chilled dough onto the prepared sheets, leaving about 2 inches between them.
- Bake for 10–12 minutes. The edges should be set and golden brown, but the centres should look slightly underdone and puffy.
- Let cookies rest on the hot baking sheet for 5 minutes before carefully transferring them to a wire rack to cool completely.