Cream the butter and sweetener. In a mixing bowl, beat softened butter with powdered keto sweetener until light and fluffy, about 2 minutes. This step builds structure and a tender crumb.

Add flavorings. Mix in vanilla, almond extract if using, salt, and the egg yolk. Beat until smooth.

Fold in almond flour. Add almond flour in two additions. Stir with a spatula until a soft dough forms. If it seems crumbly, add 1–2 teaspoons cold water or cream just until it holds together when pressed.

Shape and chill. Turn the dough onto parchment. Form into a 1.5-inch diameter log for slice-and-bake, or press into a flat disk for rolling. Wrap and chill for 45–60 minutes. Chilling prevents spreading and improves texture.

Prep the oven. Preheat to 325°F (165°C). Line a baking sheet with parchment paper.

Form cookies. For the log, slice 1/4-inch rounds with a sharp knife. For rolled cookies, roll the dough between two sheets of parchment to 1/4 inch thick and cut with a small cutter. If adding chocolate or nuts, gently press into the top of each cookie.

Bake. Arrange on the sheet with 1 inch of space. Bake 10–14 minutes, until edges are light golden. Almond flour browns fast, so watch closely.

Cool completely. Let cookies rest on the sheet for 10 minutes, then move to a rack. They firm up as they cool. Dust with powdered keto sweetener if you like.

Serve. Enjoy as-is, or pair with berries, tea, or coffee.