Heat the oven to 350°F and lightly grease a 10-inch oven-safe skillet. Whisk the almond flour, coconut flour, baking soda, and fine sea salt together.
Beat the softened butter and brown monk fruit sweetener until creamy. Beat in the egg and vanilla, then stir in the dry ingredients until a soft dough forms.
Fold the sugar-free chocolate chips into the dough. Press the dough evenly into the skillet, keeping the center slightly thinner than the outer edge.
Bake for 18 to 22 minutes, until the edges are golden and set while the center remains soft. Let the skillet cool for 10 minutes.
Melt the butter for the caramel in a small saucepan over medium-low heat. Stir in the allulose and cook for 3 to 4 minutes, stirring often, until the mixture turns light amber.
Slowly whisk in the warm heavy cream and cook for 1 to 2 minutes until smooth and glossy. Remove from the heat, then stir in the vanilla and flaky sea salt.
Spoon the warm salted caramel over the cookie skillet and let it settle for 5 minutes before serving.