Add the milk, cream, and butter to a medium saucepan. Cook over a low heat until fully combined.
Break the chocolate into squares and add to the saucepan. Stir frequently until the chocolate has fully melted.
Remove from heat and stir in sweetener and chocolate protein powder. Then stir in walnuts until all ingredients are fully combined.
Pour the mixture into a 8x8" baking dish lined with parchment paper. Let the fudge cool by placing dish into the fridge.
Once set, remove from the fridge and cut into 16 squares. Enjoy!!
Notes
If you'd prefer to use unflavored whey protein, then follow this recipe, but double your chocolate and use 3/4 cup of Swerve. Nutritional information will vary.