Line a small loaf pan or rectangular glass container with parchment paper, leaving an overhang for easy removal.

In a large mixing bowl, combine the tahini and sugar-free syrup and stir vigorously until the mixture is smooth and fully emulsified.

Gradually add the protein powder, folding it into the wet ingredients until a thick, pliable dough forms and no dry streaks remain.

Transfer the dough to the prepared pan and use a spatula to press it firmly and evenly into the corners to ensure a uniform thickness.

Place the pan in the freezer for 30 to 45 minutes until the fudge is firm to the touch and resistant to indentation.

Lift the fudge out of the pan using the parchment paper overhang and slice into 12 uniform squares using a sharp, warm knife.