Desserts Images are for illustrative purposes only, may be inaccurate, and do not guarantee the presence or absence of specific ingredients. 
Serving Images are for illustrative purposes only, may be inaccurate, and do not guarantee the presence or absence of specific ingredients. Low-Fat Fudge Bars
Rich-tasting fudgy brownie bars lightened with sweet potato puree and egg whites.
Contains common allergens
In the app, Listahan checks these against your household automatically.
Instructions
4 steps- 1
Preheat the oven to 325°F (165°C). In a bowl, combine the flour, oat bran, cocoa powder, sugar, and salt and stir to mix well.
- 2
Add the mashed sweet potato, egg whites, and vanilla extract and stir until well blended. Fold in the chopped pecans.
- 3
Coat an 8-inch square pan with nonstick cooking spray and spread the mixture evenly in the pan.
- 4
Bake for about 25 minutes, until the edges are firm and the center is almost set. Cool to room temperature, then cut into squares and serve.
Images are for illustrative purposes only, may be inaccurate, and do not guarantee the presence or absence of specific ingredients. Listahan Family Score™
71/100
Good fit for most families
Score reflects how well this recipe fits a typical busy household. In the app, your Family Score is personalized to your household's allergens, kids, and pantry.
Nutrition
per serving55
Calories
2 g
Protein
10 g
Carbs
1 g
Fat
Estimated per serving. Actual values depend on the brands and portions you use.
Listahan cooking guide
Chef notes & practical guide
Technique notes, ingredient swaps, serve-alongside ideas, storage guidance, and equipment for this recipe.
Cultural context
Low-fat baking became a mainstream American pursuit in the 1980s and 1990s, driven by dietary guidelines that emphasized reducing fat intake. Home bakers and food scientists alike began experimenting with substitutes for butter and eggs that could mimic the moistening, tenderizing, and binding functions of fat in baked goods. Sweet potato puree emerged as a notable fat replacer in brownie-style bars during this era -- its natural sweetness reduced the need for added sugar, its starch provided body, and its beta-carotene-rich moisture kept bars from drying out, unlike many low-fat alternatives that produced dry, crumbly results.
Listahan note
This version replaces nearly all added fat with mashed sweet potato, using egg whites instead of whole eggs, producing a fudge bar that is genuinely dense and satisfying without the caloric cost of a traditional brownie.
Technique cues
- The sweet potato puree must be well-mashed and smooth -- any lumps will create pockets of underdone starch in the finished bar; put the cooked sweet potato through a ricer or food mill for the smoothest result, or beat it well with a fork until completely lump-free.
- Oat bran contributes soluble fiber that mimics some of the viscous, moisture-retaining quality of fat in the batter; do not substitute rolled oats (which are coarser) as they will produce a noticeably grainier, less fudge-like texture.
- These bars are very thin (high moisture, minimal fat, low volume) and overbake quickly; begin checking at the 18-minute mark and pull them when the center barely passes the toothpick test -- the carry-over heat from the pan will finish them perfectly as they cool.
Kitchen flow
- Parallel prep
- If you have a sweet potato already baked or microwaved, these bars take under 10 minutes to assemble; cook the sweet potato the night before to streamline the process.
- Make-ahead
- The bars actually improve on day 2 as the moisture from the sweet potato redistributes through the crumb; bake the day before serving for the best texture.
- Leftover move
- Crumble leftover bars over low-fat vanilla yogurt with fresh berries for a dessert-style parfait that keeps the low-fat spirit of the original.
- Cleanup rhythm
- Line the baking pan with parchment; the bars are sticky due to their low-fat composition and will adhere to an unlined or ungreased pan, making removal difficult.
Ingredient brief
Role, handling, and swap guidance for each key ingredient.
1/2 cup mashed cooked sweet potato
fat replacer and moisture
Purpose: Sweet potato provides the moist, dense body that butter would normally contribute, along with natural sweetness that reduces the amount of added sugar needed.
Handling: Bake or microwave the sweet potato until completely tender, then mash thoroughly; cool before adding to the batter so it does not cook the egg whites prematurely.
Adaptation: Mashed ripe banana can replace sweet potato for a different but equally effective fat replacer (the flavor will be noticeably banana-forward).
1/3 cup cocoa powder
primary chocolate flavor
Purpose: Cocoa powder provides intense chocolate flavor without the added fat of melted chocolate, which is central to keeping this a low-fat bar.
Handling: Sift to remove any lumps before combining with the dry ingredients.
Adaptation: Dutch-process cocoa produces a darker, milder bar; no leavening adjustment is needed here since the recipe uses no baking soda.
2 egg whites
binding and structure
Purpose: Egg whites provide the protein structure that holds the bar together in the absence of fat; they also contribute to a slightly firmer, drier texture than whole eggs.
Handling: Use at room temperature for better incorporation; beat lightly with a fork just until combined before folding into the batter.
Adaptation: 3 tablespoons of aquafaba (chickpea brine) can replace the egg whites for a vegan version.
1/3 cup oat bran
fiber and body
Purpose: Oat bran adds soluble fiber that contributes a slightly gummy, moist quality to the bar that partially compensates for the reduced fat.
Handling: Add directly to the dry ingredients with no special prep; it hydrates fully during mixing.
Adaptation: Wheat bran can replace oat bran in equal measure but produces a slightly drier, more fiber-forward bar.
3 Tbsp chopped pecans
crunch and richness
Purpose: A small quantity of pecans adds the crunch and fat-forward richness that makes the bar feel less virtuous and more satisfying than the ingredient list suggests.
Handling: Chop roughly and distribute evenly over the top of the batter before baking so they toast in the oven.
Adaptation: Walnuts or pumpkin seeds work in the same quantity; omit entirely for a nut-free version.
Technique notes
- Mix the batter only until just combined -- over-mixing activates the starch in the oat bran and flour, which can make the bars gluey rather than fudge-dense.
- Cool completely in the pan before cutting; these bars are more fragile than fat-based brownies due to the absence of fat as a structural aid, and warm bars will tear rather than cut cleanly.
- Store with parchment between layers; the natural stickiness of the sweet potato base means bars adhere to each other without a separator.
Ingredient swaps
- Vegan direction
- Replace egg whites with 6 tablespoons of aquafaba (chickpea brine), beaten to soft foam; the bars will be slightly less firm but still cohesive.
- Nut-free direction
- Omit the pecans entirely or replace with an equal quantity of rolled oats for a crunch topping that keeps the recipe nut-free.
- Gluten-free direction
- Replace all-purpose flour with a certified gluten-free flour blend; use certified gluten-free oat bran as well, as standard oat bran is frequently cross-contaminated.
Serve alongside
- fresh raspberries or strawberries
- a small scoop of low-fat vanilla frozen yogurt
- hot black coffee to offset the sweetness
- hot black coffee
- cold unsweetened almond milk
- sparkling water with lemon
Serving suggestions only — check pairings for your household's allergens.
Storage & reheating
- Store in an airtight container, layers separated by parchment, at room temperature for up to 3 days.
- Refrigerate for up to 5 days; the texture firms up when cold but softens within 15 minutes at room temperature.
- Freeze individually wrapped bars for up to 1 month; thaw at room temperature for 45-60 minutes (these bars take longer to thaw than fat-based brownies due to their denser moisture content).
Equipment
- 8x8-inch or 9x9-inch baking pan
- parchment paper
- potato ricer or fork for mashing sweet potato
- rubber spatula for mixing and spreading
Make this household-aware
Listahan Pro checks this recipe against your household's allergens, finds pantry-aware swaps, builds the shopping list, and helps you plan the week around it.
Plan it in Listahan
Add Low-Fat Fudge Bars to your week, check it against your household's allergens, and build the shopping list automatically.
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