Walnuts can be substituted for pecans. This walnut tart is definitely an upgrade from what we have experienced until now. Nowadays, refined patisseries are more than ever based on flavors, textures and layers that should all mingle perfectly. It's been true in the French entremet world for awhile, but now even cookies and pies follow the trend. This walnut tart creation is a must try for the holidays.
Lightly toast walnuts over the stove or in the oven. Let cool. In the food processor, turn walnuts and oil into paste. Remove from the bowl and store walnut butter at room temperature. Do not clean the food processor and continue with the walnut crust. Walnut butter can be mixed with hazelnut praliné if desired (50/50). The walnut butter/spread/praliné will be used for the walnut chantilly and topping along with the ganache and dulce de lèche.
This walnut crust recipe makes about three 8''/9''(20/23cm) diameter tart.
In a food processor, process walnut to meal. Add salt, butter and sugar and smooth. Add eggs and flour. Scrape out side of the bowl as it goes. Mix until just combined. Wrap up in plastic film and refrigerate for a few hours. Pastry can be made in advance and kept refrigerated for a few days or freeze for later use. Use a third of the pastry per tart shells and freeze before baking.
For 2 pies. Cream all ingredients but the egg. Add the egg – mix well and set aside. Walnut cream can be made in advance and stored in the refrigerator for a few days. Use at room temperature.
Pre-bake oven to 350ºF/180ºC. Blind bake tart shell for 25 minutes. Pipe out walnut cream (the walnut cream recipe makes 2 pies). Bake again for 35 minutes more. Insert a toothpick into the middle of the pie and if it comes out clean, the pie is done. Remove from the oven and let stand for 10 minutes; de-mold.
Place condensed milk can (do not poke) in a saucepan. Cover with water to the top and bring to boil. Cook on low heat for 3 hours; cool. In a small saucepan, heat up caramelized condensed milk with salt to 140ºF/60ºC. Remove from the heat, transfer mixture to a narrow container – add butter and mix with an immersion blender. Use at room temperature.
Bring to a boil heavy cream with coffee beans. Cover and let infuse for about 20 minutes. Pass through a sieve over the chocolate. Let stand until chocolate melts and mix. Use ganache at room temperature.
First, make coffee extract by reducing espresso and sugar to honey consistency (see pic bellow).
Add rum, vanilla and flambé. Add maple syrup. Continue to cook until it reaches sirupy consistency again. Save 40g of rum coffee liquor for the walnut chantilly. Save the remaining liquor to moisturize the baked walnut cream tart. Add a bit more espresso or water if the liquor is a bit too thick (for the tart only).
Soak gelatin in cold water to soften, and drain. Bring to a boil the first half (250g) heavy cream with the rum coffee liquor. Sieve mixture over white chocolate and blend. Add walnut butter – mix and add gelatin. Blend well and mix in the remaining chilled heavy cream. Refrigerate overnight to set completely before whipping into soft peaks chantilly.
Transfer walnut chantilly to a chilled mixing bowl. Beat on medium-high speed, that way the air incorporates better. Do not not overwork or the mixture will separate. Moisturize pies with some rum-coffee liquor. Alternate ganache with walnut butter and dulce de lèche. Finish the tart with walnut chantilly. Garnish with dots of dulce de leche and milk chocolate shavings. Enjoy!