Purple Yam Mont Blanc by Kei Hasegawa

(This article appeared in the Spring 2020 issue of Pastry Arts Magazine)

Purple yam, also called ube, is definitely having its moment. This sweet yam is turning all sorts of desserts a vivid shade of purple, from soft serve to sponge cake to mousse. The purple yam originated in the Philippines, but is becoming increasingly popular in the U.S., thanks to lots of Instagram postings. Here I use it as the featured flavor in a classic French dessert, the Mont Blanc.

Yield: 12 servings

Cacao Almond Sablé

• 35 g almond powder
• 210 g cake flour
• 20 g cocoa powder
• 125 g unsalted butter
• 2 g salt
• 103 g confectioners’ sugar
• 55 g whole egg

1. In a bowl, combine almond powder, cake flour and cocoa powder; set aside.
2. In the bowl of a stand mixer fitted with the paddle, beat the butter until creamy. Add the salt and confectioners’ sugar and mix to combine. Add the egg and mix to combine. Add the reserved dry ingredients and mix to form dough.
3. Roll dough out to 2mm and reserve in refrigerator until chilled.
4. Once chilled, cut out twelve 22 cm x 1.5 cm strips and twelve 6 cm rounds. Line individual tart rings.
   

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Pistachio Cream

• 270 g unsalted butter
• 216 g confectioners’ sugar
• 30 g pistachio paste
• 145 g whole eggs
• 20 g egg yolks
• 10 g non-fat dry milk powder
• 320 g pistachio powder
• 30 g rum

1. In the bowl of a stand mixer fitted with the paddle, beat the butter until creamy. Add the confectioners’ sugar and mix until well blended. Add the pistachio paste and mix until combined. Add the eggs and egg yolks in three additions, mixing until blended. Add the milk powder and pistachio powder and mix until blended. Add the rum and mix to combine. Cover and reserve in refrigerator overnight.
   

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Meringue Shells

• 200 g egg whites
• 100 g granulated sugar
• 100 g dextrose powder
• 75 g confectioners’ sugar, sifted

1. In a bowl, mix the egg whites with the granulated sugar and dextrose powder. Heat up over a bain-marie to 131˚F (55˚C). Transfer to the stand mixer and, using the whisk attachment, whip to soft peaks. Fold in confectioners’ sugar.
2. Pipe the meringue on the backside of a 2 cm demisphere mold to make a shell. Place in dehydrator overnight.
   

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Granny Smith Filling

• 2 Granny Smith apples
• 50 g granulated sugar
• 5 g lemon juice

1. Cut apples into 1 cm cubes. Cook apples with the sugar and lemon juice until tender, about 10 minutes.
   

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Purple Yam Paste

• 2000 g purple yam
• 180 g glucose syrup

1. Roast the purple yams at 450˚F (230˚C) for 1 hour. Peel the yams and place the flesh in a food processor with the glucose. Process until smooth, then strain through a fine-mesh sieve.

Purple Yam Cream

• 460 g heavy cream
• 110 g egg yolks
• 50 g granulated sugar
• 13 g pectin
• 180 g unsalted butter, softened
• 1000 g Purple Yam Paste (above)

1. In a saucepan, cook the cream with the egg yolks, sugar and pectin to 185˚F (85˚C). Cool down to 113˚F (45˚C). Mix the liquid with the softened butter and Purple Yam Paste.
   

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Baking & Assembly

• Silver flakes
• Purple yam powder

1. Fill each tart shell with Pistachio Cream and bake at 350˚F (180˚C) for 25 minutes.
2. Spoon Apple Filling into meringue shell. Invert the meringue shell onto the tart base. Using a Mont Blanc tip, pipe the Purple Yam Cream over the meringue shell, covering it and mouding it up. Garnish with silver flakes and purple yam powder.