Prep your pan. Line a loaf pan or small square pan (8x8 works for thinner pieces) with parchment paper, leaving overhang for easy lifting. Lightly grease if needed so the paper sticks to the sides.

Melt the chocolate. Add the chocolate to a microwave-safe bowl. Microwave in 20–30 second bursts, stirring between each, until smooth and glossy. Alternatively, melt over a double boiler on low heat, stirring often.

Stir in the peanut butter. Add the peanut butter to the warm chocolate and whisk until completely combined and silky. If using, stir in vanilla and a pinch of salt.

Taste and adjust. If your chocolate is very dark and you prefer sweeter fudge, you can add a small amount of powdered keto sweetener. Whisk until smooth.

Pour and smooth. Scrape the mixture into your prepared pan. Tap the pan on the counter to level it and release air bubbles. Sprinkle flaky salt on top if you like.

Chill to set. Refrigerate for 1–2 hours, or until firm enough to slice cleanly. For faster setting, place it in the freezer for about 30 minutes.

Slice and serve. Lift the fudge out by the parchment, place on a cutting board, and cut into small squares. Keep portions modest—it’s rich!