Mont Blanc Eclair (モンブランエクレア)

Ingredients

Equipment Needed

• •Heavy saucepan
• •Wooden spoon or sturdy spatula
• •Piping bags
• •Large round or star piping tip for choux
• •Mont Blanc piping tip, or a small round tip as a stand-in
• •Fine sieve or potato ricer
• •Baking sheet and parchment

Instructions

1. 1

   Make pastry cream

   Heat the 300ml milk until small bubbles gather at the edge. In a bowl, whisk the yolks, sugar, and cornstarch until pale, then pour in the hot milk slowly while whisking. Return everything to the pan and cook over medium heat until it thickens and gives a few heavy bubbles. Those bubbles matter because cornstarch needs to boil briefly to set properly and lose its raw taste. Stir in the vanilla and butter, press plastic wrap directly on the surface, and chill until cold.

2. 2

   Cook the paste

   Heat the water, 120ml milk, butter, sugar, and salt in a saucepan until the butter melts and the liquid comes to a full boil. Add the flour all at once and stir hard with a wooden spoon until the dough pulls from the sides and leaves a thin film on the bottom of the pan, about 2 minutes. You're drying the dough, not punishing it. That lost moisture makes room for the eggs, and later the remaining water turns to steam and lifts the shell hollow.

3. 3

   Add the eggs

   Transfer the hot dough to a bowl and beat for a minute so the fiercest heat leaves it. Add the beaten eggs in four additions, mixing fully each time. Stop when the dough is glossy and falls from the spoon in a thick V-shaped ribbon. If it breaks off in chunks, add a little more beaten egg. If it runs like batter, you've gone too far, and the eclairs will spread instead of rising.

4. 4

   Pipe the shells

   Heat the oven to 200°C. Line a baking sheet with parchment and pipe eight straight logs, each about 12cm long, using a large round or star tip. Leave space between them because the lift comes from steam and they need room to expand. Smooth any sharp points with a wet fingertip so they don't catch and darken before the shell is done.

5. 5

   Bake until hollow

   Bake for 15 minutes at 200°C, then lower the oven to 175°C and bake 20 to 25 minutes more, until the shells are deep golden, dry, and light for their size. Don't open the oven early. The shell must set before the steam escapes, or the pastry collapses. When baked, pierce each end with a skewer and return the shells to the turned-off oven with the door cracked for 10 minutes, so the inside dries instead of softening.

6. 6

   Prepare chestnut cream

   Pass the chestnut puree through a fine sieve or potato ricer. Beat it with the kuri kanroni syrup and softened butter until smooth, adding the rum if you use it. The puree must be fine enough for a Mont Blanc piping tip, or the strands will break and sputter. Taste before you pipe. It should taste plainly of chestnut, not only sugar.

7. 7

   Whip the cream

   Whip the cold heavy cream with the powdered sugar until it holds soft peaks. Stop before it turns stiff. Soft cream gives the chestnut ribbons a gentle bed, while overwhipped cream looks grainy and makes the eclair heavy where it should be light.

8. 8

   Fill and finish

   Let the shells cool completely, then split them lengthwise or make three small holes along the bottom. Pipe in the cold pastry cream. Pipe or spoon a neat band of whipped cream over the top, then pipe the chestnut cream in thin vermicelli ribbons from end to end. Finish with one candied chestnut and a light dusting of powdered sugar. Serve the same day, while the shell still has its crisp edge.

Chef Tips

• •Chestnut puree varies wildly. If yours is already sweetened, reduce the syrup and taste as you go. Honmono here means the chestnut remains visible in flavor, not buried under sugar.
• •Use room-temperature eggs for the choux. Cold eggs tighten the dough and make it harder to judge the ribbon, which is the one sign you need to trust.
• •A Mont Blanc piping tip gives the proper fine strands. A small round tip works as a stand-in, though the look will be less threadlike. Say so honestly and the pastry keeps its dignity.
• •Fill the eclairs close to serving. Choux is hollow because it was lifted by steam, and that same hollow shell softens once cream sits inside it.

Advance Preparation

• •The pastry cream can be made one day ahead and kept refrigerated with plastic wrap pressed directly on its surface.
• •The chestnut cream can be made one day ahead. Bring it just to cool room temperature and beat it smooth before piping.
• •Unfilled choux shells can be baked earlier the same day and kept uncovered at room temperature. Re-crisp them for 5 minutes at 160°C, then cool fully before filling.

Frequently Asked Questions

Nutrition Information

1 eclair (about 155g)