Purple Sweet Potato Sandwich Loaf

I have previously shared a recipe made with regular sweet potato. It was such a delicious sandwich loaf. Now, I’ve created a Purple Sweet Potato Sandwich Loaf.

Here is another delicious loaf made with addition of purple sweet potato. I have also added an egg to the dough, for extra softness. 

Here are the details.

Ingredients

Sourdough Starter

• 7g sourdough starter
• 35g water
• 35g bread flour

Dough

• 300g bread flour (100%)
• 120g roasted and mashed purple sweet potato
• 125g water
• 1 large egg
• 30g sugar (10%)
• 60g of levain (20%)
• 6g salt (2%)
• 30g soft or melted butter(10%)
• 0.5 g dry yeast (optional, to reduce the sourness, can be added with water)

Directions 

Day 1

Starter 

• 10 pm add starter to the water and whisk together, add flour, mix well, cover loosely, let it sit at a room temp 74-78F for about 8-10 hours until starter reaches its peak (at least triples in volume).
• Roast purple sweet potato and let it cool. Mash it.

Day 2

Dough

• 8 am mix water, flour, purple sweet potato, egg, sugar, sourdough starter (60g on its peak, the rest use for future feedings), let it autolyse for 1 hour. During the autolyse process the flour becomes fully hydrated. This activates gluten development.

• 9 am mix dough on low speed of your mixing machine for 2-3 minutes, or KitchenAid on speed 3 for 3-4 minutes until well incorporated.

• Add salt, mix for a couple more minutes. The dough should come up together.
• Add soft butter, increase the speed to medium and mix for 10 more minutes until the dough is well incorporated and comes up together.
• Perform a windowpane test. Wet your hands and stretch the dough. You should be able to stretch it very thin, that’s a sign of a well developed gluten, and that your final product will have a soft and light structure.

• Cover and let the dough proof for 3-4 hours at 76-80F/ 24-28C.

• During that time perform 2 stretches and folds.
• The dough should become slightly puffy.

• 1 pm transfer the dough to the fridge for cold fermentation till the evening (for 8-9 hours).
• 10 pm remove the dough from the fridge.
• Shape as desired. I rolled it into a roll half length of a baking/loaf pan.

• Put a sheet of parchment paper on the bottom of your loaf pan, or spread butter and sprinkle some flour, inside your loaf pan.
• Transfer the shaped loaf into the loaf pan.
• Cover the dough and let it proof overnight 72F /22C until it doubles or more in volume. About 7-9 hours. Usually it doubles or more in volume by morning (6-7 am).

Day 3

• 7 am preheat the oven to 375F.
• Bake bread for 35-40 minutes until golden brown.

Enjoy your purple sweet potato sandwich loaf  🙏

Purple Sweet Potato Sandwich Loaf

1714kcal

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Prep 45 minutes mins

Cook 35 minutes mins

Overnight Levain Rise (Night 1) 8 hours hrs

Total 1 day d 1 hour hr

A striking, naturally vibrant purple sandwich loaf featuring a tender interior crumb and excellent shelf life. Incorporating roasted purple sweet potato, an egg, and butter into a sourdough base creates a delightfully soft loaf that stays fresh for days.

Servings 1 Sandwich Loaf

Cuisine Modern Artisan / Pan Loaf

Ingredients

1x2x3x

Sourdough Starter Levain (Night 1)

• ▢ 7 g Sourdough starter
• ▢ 35 g Water
• ▢ 35 g Bread flour

Main Dough (Day 2)

• ▢ 300 g Bread flour (100%)
• ▢ 120 g Roasted and mashed purple sweet potato (cooled completely)
• ▢ 125 g Water
• ▢ 1 Large Egg
• ▢ 30 g Sugar (10%)
• ▢ 60 g Active sourdough levain (20% – from stage above)
• ▢ 6 g Salt (2%)
• ▢ 30 g Softened or melted butter (10%)
• ▢ 0.5 g Dry yeast (optional, added with water to reduce sourness)

Equipment

• ▢
  Kitchen Scale
• ▢
  Stand Mixer (fitted with dough hook attachment)
• ▢
  Standard Loaf Pan
• ▢
  Parchment Paper (or butter for greasing pan)

Method

Prevent Sleep ModePrevent Sleep Mode

1. Night 1: Build Levain & Roast Potato (10:00 PM)

1. In a small jar, whisk 7 g starter into 35 g water, then add 35 g bread flour. Cover loosely and let ferment at room temperature 74–78°F (23–26°C) for 8–10 hours until peak (at least triples).
2. Roast purple sweet potato until fork-tender, cool completely, and mash thoroughly until smooth.

2. Day 2: Mixing & Cold Retard

1. Autolyse (8:00 AM): In stand mixer bowl, combine 125 g water, 300 g bread flour, 120 g purple sweet potato mash, 1 large egg, 30 g sugar, 60 g active levain, and optional 0.5 g dry yeast. Cover and let autolyse for 1 hour.
2. Mixing (9:00 AM): Knead on low speed for 2–3 minutes (or KitchenAid speed 3 for 3–4 minutes). Add 6 g salt and mix for 2 more minutes until a cohesive ball forms.
3. Butter Incorporation: Add 30 g soft/melted butter, increase speed to medium, and knead for 10 minutes until smooth and passes the windowpane test.
4. Bulk Proofing: Cover and proof for 3–4 hours at 76–80°F (24–28°C), performing 2 stretch-and-folds during this window until slightly puffy.
5. Cold Retard (1:00 PM): Transfer dough container to refrigerator for 8–9 hours of cold fermentation.

3. Night 2: Shaping & Overnight Proof (10:00 PM)

1. Remove dough from fridge. Roll into a smooth cylinder half the length of your loaf pan.
2. Line bottom of loaf pan with parchment paper (or grease with butter and dust with flour). Place shaped roll into pan.
3. Cover dough and let proof overnight at 72°F (22°C) for 7–9 hours until doubled or more in volume (rising past the pan rim by morning).

4. Day 3: Bake (7:00 AM)

1. Preheat oven to 375°F (190°C).
2. Bake loaf for 35–40 minutes until golden brown on top.
3. Cool completely on a wire rack before slicing.

Nutrition

Calories1714kcalCarbohydrates299gProtein48gFat34gSaturated Fat18gPolyunsaturated Fat4gMonounsaturated Fat8gTrans Fat1gCholesterol228mgSodium2662mgPotassium813mgFiber12gSugar36gVitamin A18018IUVitamin C3mgCalcium125mgIron5mg

Notes

• The Starch Secret Behind Ultra-Soft Sandwich Loaves: Incorporating mashed potatoes into bread dough is an old-world baking secret for creating a cloud-like texture. Potatoes are packed with gelatinized starches that disrupt the wheat gluten network just enough to prevent the crumb from turning tough or rubbery. Furthermore, these starches hold onto moisture significantly longer than wheat flour alone, keeping your sandwich slices soft and fresh for days without stale staling.
• Why the Final Pan Rise Happens Overnight on the Counter: Enriched doughs packed with dense potato flesh, eggs, sugar, and butter ferment significantly slower than standard lean flour-and-water artisan loaves. Giving the shaped pan loaf a slow, 9-hour room temperature proof on your kitchen counter overnight allows the wild yeasts to work steadily over many hours, ensuring a gorgeous, towering oven spring by the time you wake up.
• Achieving an Ultra-Smooth Potato Mash: To avoid unappealing pockets of unmixed potato throughout your beautiful purple crumb, ensure your sweet potato is boiled until completely falling apart. Running the hot potato chunks through a fine mechanical potato ricer or a mesh sieve yields a silky, velvety paste that incorporates seamlessly into the milk and flour matrix during the autolyse stage.

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