Prepare the Foundation : Position a rack in the center of your oven and preheat to 325°F (165°C). Place the oven-safe skillet over low heat on the stovetop.
Melt & Bloom : Add the butter to the skillet, allowing it to melt completely. Turn off the heat. Immediately whisk in the black cocoa powder and instant espresso powder until a smooth, fragrant paste forms. Blooming the cocoa this way deepens its flavor.
Sweeten the Base : Pour the granular sweetener blend into the warm chocolate mixture. Whisk vigorously for about one minute until the batter is glossy and well-combined.
Incorporate Eggs & Vanilla : Crack the eggs directly into the skillet, one at a time, whisking well after each addition until fully integrated. The mixture should become shiny and slightly thickened. Stir in the vanilla bean paste.
Fold in Dry Goods : Sprinkle the almond flour, xanthan gum, and sea salt over the wet ingredients. Switch to a spatula and fold gently until no dry streaks remain. Be careful not to overmix.
Final Touches & Bake : Stir in the chopped walnuts and half of the sugar-free chocolate chips. Smooth the batter evenly in the skillet with the spatula and scatter the remaining chocolate chips on top. Transfer the skillet to the preheated oven.
Bake to Fudgy Perfection : Bake for 22–25 minutes. The brownies are done when the edges are visibly set and a toothpick inserted into the center comes out with moist, fudgy crumbs attached, but no wet batter. The center should have a slight wobble.
Cooling is Crucial : Remove the skillet from the oven and place it on a wire rack. The brownies will continue to set as they cool in the hot pan. Allow them to rest for at least 15 minutes before slicing and serving.
