Preheat oven to 180°C (375°F). Line two cookie sheets with parchment paper. Set aside.
In a large mixing bowl, beat the soft butter with erythritol and golden erythritol until light and fluffy. It should take about 45 seconds at medium speed.
Stop the beater, then add in the egg, vanilla, almond extract, salt, baking soda, and xanthan gum. I highly recommend xanthan gum as this adds a chewy texture to your cookies, preventing the cookies from crumbling.
Beat again on low speed until creamy.
Beat in the almond flour on medium speed, adding the flour 1/2 cup at a time. The batter will be fluffy and more difficult to beat as it goes. That is what you want.
Stop the beater and stir in the chocolate chips with a spatula.
Refrigerate the dough for 5 minutes.
Scoop out 3 tablespoons of dough per cookie and transfer onto a baking tray, covered with a piece of parchment paper. Leave a 2-thumb space between each cookie as they will expand during baking.
Depending on the texture and shape you aim to, slightly flatten each cookie ball into a disc. For ultra-thin, wide cookies, flat in the center, press the cookie to 4 mm (0.2 inches). For a thicker, softer/fluffier cookie, give a small press and barely flatten the dough. Remember that the thinner, the crispier they will be in the center. Read my blog post above to learn all my tips on how to get your favorite cookie texture.
Bake 10-12 minutes, in the center rack, until golden on the side but still white and soft in the middle.
Remove rack from the oven and cool the cookies on the rack for 12 minutes. Don't touch them at this point. They can be fragile and crumbly.
After 12 minutes, slide a spatula under each keto chocolate chip cookie to transfer them to a cooling rack.
Cool 20 more minutes on the cooling rack before eating. Note that the cookies will get their final texture only after 4 hours on the cooling rack at room temperature. For a crispier cookie, store it in the fridge! Serve with a pinch of salt to enhance the flavors.
Store in a cookie jar for 3 days at room temperature or 1 week in the fridge. Freeze in ziplock bags. Defrost on the counter at room temperature for 3 hours before eating.
Vegan: the recipe is not recommended with a flaxseed egg or coconut oil or vegan shortening.