Prep the pan: Line an 8x8-inch square pan with parchment, leaving overhang on two sides for easy lifting. Lightly spray the parchment if it tends to stick.

Set up a gentle heat: In a small saucepan over low heat, add the butter and coconut milk (or heavy cream). Warm until the butter melts and the mixture steams, but do not let it boil.

Melt the chocolate: Add chopped unsweetened baking chocolate to the warm mixture. Stir constantly until smooth and glossy. Keep the heat low to avoid scorching.

Stir in nut butter: Add the nut butter and mix until fully incorporated. The mixture should look thick and unified.

Add sweetener and cocoa: Whisk in powdered sweetener and cocoa powder. Taste and adjust sweetness if needed. If the mixture tastes slightly less sweet than you want, that’s perfect—chilled fudge tastes a bit sweeter.

Finish with flavor: Remove from heat. Stir in vanilla extract and a pinch of fine sea salt. If using espresso powder or orange zest, add it now.

Optional mix-ins: Fold in chopped nuts or cocoa nibs for texture.

Pour and smooth: Scrape the mixture into the prepared pan. Smooth the top with a spatula. If using flaky sea salt, sprinkle a small pinch over the surface.

Chill to set: Refrigerate for 2–3 hours, or until firm enough to slice cleanly. For faster setting, place in the freezer for 45–60 minutes.

Slice and serve: Lift the fudge out using the parchment overhang. Cut into small squares (about 1–1.5 inches). A hot, dry knife helps make tidy cuts—dip in hot water, wipe dry, then slice.