Mix all ingredients until well combined. Press into an 11x7 inch pan (or similar size—you could use a 9x13 pan, but not press them all the way to one side). Refrigerate for at least 1 hour before cutting into bars.
Before cutting, press them down and together tightly. Store bars in an airtight container in the fridge for up to 2 weeks.
Freezing Instructions: Layer bars in a freezer safe bag or container, with a piece of parchment paper between layers, and freeze for up to 3 months. Thaw in the refrigerator or on the counter before eating.Protein Powder: Use your favorite kind. Chocolate, vanilla, or plain would all work great for this recipe, or try half protein powder and half unflavored collagen peptides.Chocolate Protein Bars: Use chocolate protein powder. Nut Butter: Swap out the peanut butter for almond butter, cashew butter, or sunflower butter.Vegan Protein Bars Recipe: Use your favorite vegan protein powder.