Heat the oven to 350°F (177°C) and cover a baking sheet with parchment paper. Set up the pan before mixing so the shaped dough can go straight into the oven.

Beat the softened butter with the powdered erythritol in a bowl until creamy and uniform. The mixture should look smooth and feel fluffy rather than slick with melted butter.

Mix in the egg and vanilla extract until the mixture becomes fully blended. Scrape the bowl as needed so no streaks of egg remain around the sides.

Stir in the almond flour, cinnamon, and salt until the mixture becomes a soft dough. Stop once the flour disappears and the dough gathers together without loose dry patches.

Divide the dough into 12 portions, roll each into a ball, flatten it, and press a whole almond into the center. Keep the cookies similar in thickness so their edges color at the same pace.

Bake for 15–18 minutes, then leave the cookies on the baking sheet until completely cool before lifting them. Remove them when the edges are lightly golden and the cinnamon aroma is warm and toasty.