Preheat oven to 375°F (190°C). Line a baking sheet with parchment. Mix cinnamon + erythritol in a small bowl for topping.
In a bowl whisk almond flour, psyllium husk, baking powder, salt (and optional erythritol).
In another bowl whisk eggs and stir in 2 tbsp melted butter. Pour wet into dry. Mix until a sticky dough forms. Let rest 3–5 minutes.
Divide dough into 12 equal pieces. Roll each into a rope and shape into pretzels (or make simple knots).
Place on baking sheet, brush with some melted butter. Bake 13–16 minutes until edges lightly golden.
Remove, brush immediately with remaining butter, then press into cinnamon-erythritol coating. Cool on a rack. Serve warm or at room temp.