Purple sweet potato mont blanc tartlets

I bought some purple sweet potato few days ago and had some leftover so I decided to make one recipe that I've been eyeing for quiet sometime .

Mont Blanc or chestnut cake is a dessert made from puréed , sweetened chestnuts , decorated with chestnut pastry cream and dusted with icing sugar . The name is derived from the highest mountain in the Alps , as it resembles a snow-capped mountain .

This is a Japanese-style version using purple sweet potato . It has 4 components , the tart base , almond cream , créme chantilly and sweet potato cream . It may look a bit complicated and too much work but once you've assembled all components , making it was pretty easy . Well , making the pâte sucrée or the sweet shortcrust pastry was a breeze but I had a hard time fitting each piece of pastry dough into the pastry rings and had to re-roll the dough twice . Good thing that the tart base turned out delightfully crunchy in every bite .

I had an issue with straining the mashed sweet potato as well , it took me as long as fitting all those dough into the pastry rings ! A necessary evil though as it resulted in a smooth , creamy and easily piped sweet potato cream .

As you can see the cross section of a tart below , it looks as if it only have 3 components instead of 4 . I think the pastry tart base need more baking time as the color is a bit pale at the bottom or maybe our oven is acting up again tsk ! That said , the texture of the tart base is still crunchy despite the pale color . These tarts are best eaten the day they're made , if you chill it overnight , it will lose some of its crunchiness but still delicious nonetheless .

East meets West delicate pastry with layers of wonderful flavours and texture , these pretty Japanese-style mont blanc tarts are a sure winner ! 

Pâte sucrée , recipe adapted from Bouchon Bakery cookbook via Serious Eats

Makes 837 grams tart dough ( I used half and freezes the other half for future use , hopefully ) 

375 grams all-purpose flour
46 grams icing sugar
47 grams almond flour
225 grams unsalted butter , at room temperature
94 grams icing sugar
1/2 vanilla bean ( I used 4 1/2-inch whole vanilla bean )
56 grams whisked egg

* Place flour in a medium bowl , sift in the 46 grams icing sugar and almond flour into the bowl . Break up any lumps of almond flour remaining in the sieve and add them to the bowl , whisk to combine .

* Place butter in a large mixing bowl , using an electric handmixer , beat over medium-high speed until butter is the consistency of a mayonnaise and hold a peak when beater is lifted . Sift in the remaining 94 grams icing sugar and beat on low for few seconds so that sugar won't fly around then increase to medium high and beat until mixture is fluffy , about 2 minutes . Scrape down bottom and sides of the bowl as needed . Scrape the seeds from vanilla beans and add them to the butter mixture , mix on low speed for about 1 minute to distribute seeds evenly .

* Add dry ingredients in 2 additions , mixing for about 1 minute or just until combined . Scrape the bottom of the bowl to incorporate any dry mixture that have settled . Add whisked egg and mix on low speed , about 1 minute .

* Transfer dough into the work surface , use the heel of your hand to smear the dough , maybe 6 times then gather the dough and pat it into a rough ball . Weigh the dough in half and form each half into a 4x6-inch rectangle , about an inch thick . Wrap each piece in a double later of plastic wrap . Refrigerate until firm , about 2 hours , preferably overnight .

* Roll out the 4x6 rectangle ( mine is more of an oval ) of pastry dough , about 1 cm thick , use a round cutter slightly bigger than the pastry rings that you're using . I used four 3 1/4 x 1/2-inch and two 2 3/4 x 1/2-inch round pastry rings . There were some leftover dough , maybe good for 2 more .

* Fit in dough into the pastry rings , trim the top and prick the bottom with fork , chill in the fridge until needed .

Almond cream , recipe adapted from Washoku guide / Cookpad

35 grams butter
35 grams icing sugar
35 grams whisked egg
35 grams almond meal / flour
1/2 tsp rum

* Mix all ingredients above until smooth .

Créme chantilly / whipped cream 

150 grams double cream
15 grams caster sugar

* Beat ingredients over high speed until soft peaks form . Chill in the fridge until needed .

Purple sweet potato cream 

210 grams ( steamed ) mashed purple sweet potato
30 grams caster sugar
30 grams milk
1 tsp rum , optional
60 grams créme chantilly

* Combine together sweet potato , sugar , milk and rum , mix well . Press mixture through a strainer to get rid of the lumps , it can take a while but very important . Add créme chantilly to the sweet potato mixture and mix well to combine . Place in a piping bag fitted with a plain small round tip or a mont blanc piping nozzle ( one with several small holes ) .


 * Preheat oven to 170ºC . 

* Take out pastry tarts from the fridge and divide the almond cream among them , smoothing the top .  Chill for another 10 minutes .

* Bake for 25 minutes or until pastry is golden . Take out from the oven and let cool in the wire rack completely , remove rings from the cooled pastry tarts .

To assemble Mont Blanc : 

* Place créme chantilly in a piping bag fitted with a 1 cm round nozzle . Pipe a mound of cream on top of tart then pipe the sweet potato cream around it , continue with the rest .


  1. Very clever, Anne, to put together such a beautiful tartlet. Love the vibrant purple of the sweet potato. I don't think I can handle so many components. Anyway thanks for sharing Anne.

  2. Wow, so many exquisite layers! These are gorgeous tarts!!!

  3. Oh my word Anne, your tarts are so beautiful. You have such patience and creativity to take each step one at a time to utter perfection. I really need to learn to have more patience when I bake. Just look at the results and I can only imagine how delightful the layers must meld together in taste.

    Thank you so much for sharing, Anne...your did wonderfully! Pinning:)

  4. These purple sweet potato tartlets look absolutely divine! I love esp. that purple potato cream. Well done, Anne.


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