French AmericanMedium · Hot
Sunflower Seed-Crusted Sweet Potato Gratin
A comforting, allergen-free twist on the classic French gratin — thinly sliced sweet potatoes layered with herbs and silky cream, finished with a golden sunflower seed crust that delivers satisfying crunch in every bite.
Prep
20 min
Cook
50 min
Rest
10 min
Total
1h 20m
Method
Prep
2
Peel the sweet potatoes and slice them very thin, about 1/8 inch thick. A mandoline makes this quick and ensures even slices.
3
In a small saucepan over medium heat, combine the heavy cream and salt. Warm gently until small bubbles form around the edges, about 5 minutes. Remove from heat.
4
In a food processor, pulse the sunflower seeds, olive oil, and salt until you have a chunky, crumb-like mixture with some smaller seeds and some larger pieces for texture.
Assemble
5
Arrange one third of the sweet potato slices in overlapping rows in the prepared baking dish. Season lightly with salt and black pepper.
6
7
Add a second layer of sweet potato slices, season again, and add remaining garlic and thyme. Pour another third of the cream sauce.
8
Finish with the final layer of sweet potato slices. Pour the remaining cream sauce evenly over the top.
9
Press the sunflower seed mixture firmly onto the top layer of sweet potatoes, creating an even crust.
Bake
11
12
Let rest for 10 minutes before serving. This allows the layers to set for cleaner slices. Garnish with fresh parsley.
C
Nutri-Score
Fair balance
A–E · lower is better · score 10
Calories
470
per serving
High in saturated fat · 10gCalorie-dense · 470 kcalSource of fibre · 5gLow sugar · 6g
Protein
9g
Carbs
19g
Fat
42g
Sat. fat
10g
Fiber
5g
Sugar
6g
Sodium
844mg
Allergen AdaptableLow CarbNutrient DenseWhole Food
Nutri-Score is a general nutritional-balance guide, not medical or dietary advice.
B
Environmental impact
Low impact
A–E · lower is better · includes estimates
kg CO2e
0.4
per serving
BCarbonAEU all-round· carbon sets the grade
Water
0.2m³
Land
26Pt
Runoff
0.05g P
Heavy Cream drives 79% of this recipe’s estimated footprint.
Carbon from Poore & Nemecek 2018; water, land & runoff from Agribalyse — modelled averages for comparing recipes, not a measurement of your groceries.
Flavor Profile
5
Umami
4
Sweet
5
Salty
1
Sour
1
Bitter
3
Spicy
Textures
CrispyCreamyTenderSilky
Aromas
HerbalNuttyGarlickyButtery
Kitchen Equipment
Primary Tool
OvenCounter FootprintMedium
Safety & Storage
Cross Contamination
Thoroughly wash the mandoline and food processor between uses if also preparing allergen-containing dishes. Use dedicated cutting boards and utensils for dairy-free meal preparation.
Cooking Temperature
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Storage
Refrigerate leftover gratin within 2 hours of serving. Store in an airtight container for up to 4 days. Reheat to 165°F (74°C) before consuming leftovers.
Handling
Use caution when handling the sharp mandoline for slicing sweet potatoes. Wear protective gloves if inexperienced with the tool. Allow gratin to rest 10 minutes before slicing to allow layers to set properly.
High Risk Population
This dish contains dairy. For individuals with lactose intolerance or milk allergies, heavy cream can be substituted with full-fat coconut cream as a dairy-free alternative while maintaining the creamy texture.
Allergen Warning
Sunflower seeds, while not a top-14 allergen, may cause reactions in individuals with seed allergies. Verify guest seed allergies before serving.
CRITICAL: This recipe contains heavy cream (dairy) and sunflower seeds. Do NOT serve to individuals with milk allergies or seed allergies. Despite appearance in dietary tags, this dish is NOT dairy-free or allergen-free.
Shelf Life
Prepared gratin is best consumed within 24-48 hours for optimal texture and flavor. The crispy sunflower seed crust will soften during refrigeration.
Pro Tips
Technique
A mandoline slicer is your best friend here — consistent 1/8-inch thickness means every slice cooks evenly, so you won't have some tender and some crunchy in the same layer. Take the extra minute to set that depth gauge.
Equipment
Pulse your sunflower seed crust in short bursts rather than running the food processor continuously. You want a mix of fine crumbs and larger pieces — that texture variety is what creates those satisfying golden crunch bits on top.
Make Ahead
Assemble the gratin up to the point of baking, cover tightly, and refrigerate for up to 24 hours. When you're ready to serve, add 10 extra minutes to the covered baking time — the flavors actually deepen overnight.
Substitution
Pepitas (hulled pumpkin seeds) work beautifully in place of sunflower seeds if you need to rotate allergens or simply prefer a milder flavor profile. Process them the same way for comparable crunch.
Reheating
For the crispiest leftovers, reheat uncovered at 375°F for 15-20 minutes rather than microwaving. The top will perk back up to golden and the cream will redistribute beautifully through the layers.
From the chef
Thinly sliced sweet potatoes layered with minced garlic, thyme, and warm cream — this gratin follows the classic French method closely, and the result speaks for itself. What changes is the crust: sunflower seeds pulsed with olive oil and salt into a coarse, crumbly topping that turns deeply golden in the oven and stays crisp even after resting. The layers beneath become silky and yielding, sweet and fragrant with herbs. Cover for the first half of baking, uncover for the second, and you get that satisfying contrast of tender inside and crackling top that makes everyone reach for a second portion.
TagsComfort FoodVegetarianGluten FreeSeasonalHerb SeasonedBakedCrispy Topping
AllergensMilk
Source: generated · June 10, 2026