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Mocha Mont Blanc Tart

Sweetened chestnut purée, chocolate ganache and kahlua laced whipped cream all hang out in a tender walnut crust. A perfect winter dessert, that is deceptively easy to make.

Course Dessert
Cuisine French
Keyword chestnut purée,coffee,chocolate,buckwheat flour,cinnamon,whipped cream,no bake
Prep Time 30 minutes
Cook Time 1 hour
Servings 8

Ingredients

Walnut Tart Crust

  • 2 1/2 cups walnuts can also use almonds, hazelnuts etc or a combo of two
  • 3-4 tbsp rye or buckwheat flour
  • 5 tbsp butter softened
  • 3 tbsp muscovado or brown sugar
  • 1 tbsp fine espresso powder regular ground coffee can be used if ground down finer with a mortar and pestle
  • 1/4 tsp salt

Chocolate Ganache

  • 1/4 cup heavy cream
  • 4 oz dark chocolate at least 70% cocoa, chopped into 1/4 inch pieces
  • 1 tbsp fine espresso powder regular ground coffee can be used if ground down finer with a mortar and pestle

Chestnut Purée

  • 400 g chestnuts boiled, peeled and ready to eat, cut into smaller pieces
  • 200 g granulated sugar
  • 2 teaspoon vanilla extract
  • 1 tbsp fine espresso powder see above
  • 250 milk
  • 250 g water

Whipped Cream topping

  • 1 cup 250 ml of 35-40% whipping cream
  • 2 tbsp icing sugar
  • 1 tbsp cornstarch
  • 1 tbsp Kahlua optional
  • 2 tbsp Chocolate Curls for garnish
  • 6-8 Candied Chestnuts

Instructions

Crust

  1. Preheat oven to 375F, and grease a 9 inch tart pan with a removable bottom.
  2. Place all ingredients, using 3 tbsp of the flour into a food processor and grind until a small crumb is achieved. If it seems too wet or sticky, you can add a bit more flour.
  3. Line the tart shell with a removable bottom with the crumbs. Smooth out evenly. Add some parchment paper and dried beans to keep the crust in place while baking.
  4. Bake on centre rack until the crust is browned and set, about 10-15 minutes. After 8 minutes you can remove the paper and beans and let it continue baking. Let it cool before adding the ganache. This can be made the day before and stored in the fridge, sealed well.

Ganache

  1. Heat the cream over medium heat in a small bowl. Heat till just under boiling.
  2. Remove from the heat and add the chocolate and coffee. Swirl the cream around to cover all the chocolate.
  3. Let it sit for 5 minutes. Then whisk gently to combine. Scrape it into the cooled tart shell, turning the shell slightly to get the ganache to go up the sides a bit. Set this into the fridge to completely set.

Chestnut Purée

  1. In a saucepan, add the boiled chestnuts, sugar, vanilla extract, milk and water.
  2. Boil, and then reduce to a rolling simmer without a lid for 25-30 minutes.
  3. As soon as the liquid level reduces and there is about 2 cm of liquid left in the saucepan, remove from heat.
  4. Transfer the contents of the saucepan to food processor and beat until all of the ingredients are completely combined and puréed. If you find that the purée is very thick, you can add a touch more water to help it smooth out. But remember, you do want a thicker purée, not too creamy a mixture, or else it won't pipe through your potato ricer.
  5. (If you don't have a potato ricer and are planning on just spooning the purée gently over the set ganache, then it is alright to have it be a bit creamier. But still, don't let it become soupy.)
  6. Transfer to a bowl and store in the fridge till needed. This will keep in the fridge for 10 days, in a well sealed container.
  7. When ready, using two cups of the prepared purée, take spoonfuls and your potato ricer, and push the purée through onto the chocolate ganache layer. Move the ricer around to have the purée land in layers evenly over the shell. Continue till about two cups have been used. You will have leftover purée. Feel free to use it on toast, stuffed in crepes etc.
  8. Alternately, you can gently spoon and smooth the chestnut purée over the chocolate ganache till you have about 3/4- 1 inch of filling spread out.

Whipped Cream

  1. Combine the icing sugar and cornstarch with a small whisk in a bowl. Set aside.
  2. Starting on the lower speed of your stand mixer, whip the cream. Slowly add the sugar mixture and increase the speed till on high. Whip till almost firm with peaks. Add some Kahlua (or not) and blend a bit more.
  3. This can be prepared ahead of time.
  4. Mound the whipped cream on top of the chestnut purée, allowing the outer edge to be revealed. Mound it so that it is higher in the middle, echoing the shape of a mountain.
  5. Sprinkle chocolate curls over the cream. Garnish with candied chestnuts if so desired.

Recipe Notes

This will keep, covered in the fridge for a few days.

You will have enough leftover purée to use on toast, in crepes, or even in oatmeal.  Enjoy.