Step 1: In a heat-safe bowl, sprinkle the unflavored gelatin powder over 1 cup of cold water. Let it 'bloom' for 5-10 minutes until it becomes thick and spongy.
Step 2: Pour 1 cup of boiling water into the bowl with the bloomed gelatin. Whisk continuously until the gelatin is completely dissolved and there are no granules remaining.
Step 3: Add the contents of the sugar-free JELL-O® mix package to the dissolved gelatin mixture. Whisk thoroughly for about 2 minutes until the JELL-O® powder is fully incorporated and dissolved.
Step 4: In a separate bowl or shaker bottle, combine 1 cup of cold water with the protein powder. Mix until the protein powder is completely smooth and lump-free.
Step 5: Gently pour the protein powder mixture into the JELL-O® mixture. Whisk slowly and steadily until well combined, being careful not to create excessive foam.
Step 6: Carefully pour the combined mixture into an 8x8 inch glass baking dish or a silicone mold. Lightly spray the dish with cooking spray if desired, to ensure easy removal.
Step 7: Refrigerate for at least 4-6 hours, or preferably overnight, until the JELL-O® is completely set and firm to the touch.
Step 8: Once set, use a sharp knife (dipped in hot water for cleaner cuts) to cut the High Protein JELL-O® into desired cube sizes. Carefully remove the cubes from the dish.
Step 9: Store the High Protein JELL-O® Cubes in an airtight container in the refrigerator for up to 5-7 days.