Preheat your oven to 350°F (175°C). This is crucial for achieving that perfect cookie texture.
In a large mixing bowl, combine the melted butter, light brown sugar, and granulated sugar. Whisk until well combined and smooth. Add in the large egg, egg yolk, and vanilla extract, mixing until creamy.
In a separate bowl, whisk together the all-purpose flour, whole-grain buckwheat flour, baking powder, baking soda, and salt. This step ensures that your leavening agents are evenly distributed throughout the flour.
Gradually add the dry ingredients to the wet mixture, stirring gently with a spatula until just combined. Be careful not to overmix, as this can lead to tough cookies.
Gently fold in the coarsely chopped chocolate, roasted buckwheat groats or cocoa nibs (if using), and the chopped nuts. The dough will be thick and chunky—just how we want it!
Using an ice cream scoop or a spoon, drop heaping tablespoons of dough onto the prepared baking sheet, leaving enough space between each cookie to allow for spreading. Sprinkle a bit of flaky sea salt on top of each cookie for that perfect sweet and salty contrast.
Place the baking sheet in the preheated oven and bake for 10-12 minutes, or until the edges are lightly golden. The centers may look slightly underbaked, but they will firm up as they cool.
Remove the cookies from the oven and let them cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely. Enjoy these Buckwheat Chocolate Chip Cookies warm or at room temperature.
