Richest Peanut Butter Protein Brownie for One (Sugar Free)

A half baked peanut butter protein brownie for one with a fudgy gooey center. This healthy, sugar free, gluten-free peanut butter brownie uses peanut butter powder and protein powder for a rich, single serve dessert.

This one happened almost by accident. Back in the early days of the blog, I was trying to post a new recipe to Instagram every single day - before I figured out that reposting old content was a completely acceptable thing to do. Most days that meant scrambling for something easy enough to pull together and photograph before I ran out of daylight.

One of those days, I thought back to my Half Baked Protein Fudge Brownie and figured: why not turn it into a chocolate peanut butter version? That combination is basically un-improvable - a classic for a reason.

So that's how this one was born: a last-minute, single-serving brownie that turned out just as fudgy and rich as the original, minus the sugar, plus a very good excuse to eat peanut butter for dessert.

Ingredients for This Peanut Butter Protein Brownie

This single serve peanut butter protein brownie is made with a few simple, healthy ingredients, and has no butter or oil and no sugar either.

• Chocolate Protein Powder for high protein brownie that's also sugar free.
  I use Quest Chocolate Whey-Casein Protein Powder here - the whey-casein blend holds up best for baking and keeps this brownie fudgy instead of dry.
  • Sub: Use vanilla protein powder instead if that's what you have.
• Unsweetened Cocoa Powder or Cacao Powder
• Peanut Butter Powder,  also known as powdered peanut butter. I use PB2 or PbFit for this - both keep it sugar free.
  • Sub: Use 1 tablespoon creamy peanut butter instead, but reduce the milk to about 3½ Tbsp.
• Coconut Flour - this is what gives the brownie its structure, but a little goes a long way since it absorbs a lot of liquid.
  • Sub: Try about 3 tablespoons of almond flour instead.
• Egg Whites for extra protein and to help bind the batter together.
  • Sub: 2 tablespoons aquafaba (chickpea liquid) - I haven't tried this one myself yet.
• Unsweetened Almond Milk
  • Sub: Any other milk works.
• A bit of Vanilla Extract
• Baking Powder
• A pinch of salt (optional, but it sharpens the chocolate and peanut butter flavor)

And some Creamy Peanut Butter for topping - I love using American Dream Nut Butter here since it's high protein on its own. Use code HAYLSKITCHEN for a discount on your order.

TIP: If you need more sweetness, stevia powder or a zero calorie sugar substitute like Swerve keeps this batter sugar free.

TIP 2: Fold in a tablespoon of Lily's Dark Chocolate Chips or ChocZero Mini Chocolate Chips for extra texture.

A Vegan Peanut Butter Fudge Brownie Recipe

This gooey peanut butter brownie recipe has no butter or milk and can easily be made vegan too. For the perfect vegan version, use a plant based protein powder -Dymatize Complete Plant Chocolate,KOS Plant Chocolate, or Truvani Plant-Based Chocolate all work well here - and aquafaba in place of the egg whites. Since the almond milk is already dairy-free, this swap gets you a fully dairy-free brownie too.

Tips to make Peanut Butter Protein Powder Brownie in a Mug

This fudgy peanut butter protein powder brownie really is an easy one and made in a mug or ramekin, but make sure you do all of this stuff to get is perfect.

• Grease the ramekin! You want the brownie to come off easily.
  Use an oven-safe mug if you need.

• Don't over-mix the batter!
  Make sure you gently fold the dry mix into the wet to combine them.
  If you over-mix it,  protein powder will make your protein brownie tough, dense and gummy.

• Taste the batter and see if you need some extra sweetener. I'd recommend using stevia powder to maintain the consistency of the batter.

• Don't overbake the brownie. The top will should be just cooked. It might look soft, but will harden when it cools a bit.
  It will continue to cook when out, and you want the proper fudgy peanut butter brownie center.

Tips to Make This Peanut Butter Protein Powder Brownie in a Mug

This fudgy peanut butter protein powder brownie really is an easy one, made in a mug or ramekin - but a few things make the difference between good and perfect.

• Grease the ramekin. You want the brownie to come off easily. Use an oven-safe mug if you need to.
• Don't over-mix the batter. Gently fold the dry mix into the wet to combine. Over-mixing makes the protein powder turn your brownie tough, dense, and gummy.
• Taste the batter and see if you need extra sweetener. I'd recommend stevia powder to keep the batter's consistency intact.
• Don't overbake the brownie. The top should be just cooked - it might look soft, but it'll harden as it cools. It keeps cooking a bit once out of the oven, which is what gets you that proper fudgey center.

How to Store Peanut Butter Protein Brownie

This one's best fresh out of the oven while the center's still gooey, but leftovers hold up fine.

• Fridge: Store covered in the ramekin or an airtight container for up to 3 days. Microwave for 15-20 seconds to warm back up.
• Freezer: Wrap tightly and freeze for up to 1 month. Thaw overnight in the fridge, or microwave straight from frozen in short bursts.

More Single Serving Protein Brownie Recipes

• Half Baked Oreo Protein Fudge Brownie
• Half Baked Protein Fudge Brownie
• Air Fryer Protein Brownie
• Single Serve Protein Brownie