Text Susan Jung / Photography Jonathan Wong / Styling Nellie Ming Lee
I created this tart while trying to lighten the flavours of a chocolate and walnut version. I decided to add a layer of Seville orange (also called bitter orange) marmalade for two reasons: first, because the citrus flavour would add a bright note to the tart, and second, because I had made a huge batch of the marmalade and wanted to find ways of using it, other than just spreading it on toast. Don't worry about making your own marmalade, though - just buy it. It's not difficult to make, but bitter oranges aren't easily available (or cheap) in Hong Kong.
Chocolate, walnut and Seville orange tart (pictured)
This dough is quite soft and delicate to work with because it has a high proportion of nuts but, when baked, it makes a tender crust that almost melts in the mouth. You can also make the dough into cookies: shape it into a very tight, firm cylinder that's about 2cm in diameter. Wrap the dough in parchment, then refrigerate it for several hours, or until it's firm. Unwrap the dough and brush the entire length of it with egg white that's been whisked until frothy, then roll the cylinder in granulated sugar. Cut the cylinder into slices about 5mm thick, then lay the pieces on a baking tray lined with parchment paper. Bake at 180 degrees Celsius for about 10 minutes, or until the cookies are fragrant and firm. Cool the cookies before eating and store them in an air-tight container.
The dough recipe is enough for four tarts; the rest can be wrapped in cling-film and frozen for a couple of months.
For the dough:
100 grams walnut pieces
190 grams icing sugar
¼ tsp fine sea salt
60 grams Dutch-process cocoa powder
400 grams plain (all-purpose) flour, plus extra for rolling the dough
300 grams unsalted butter, slightly softened and cut into 2cm chunks
2 large eggs, chilled
1 tsp vanilla extract
For the filling:
160 grams walnut pieces
70 grams light muscovado sugar
70 grams granulated sugar
1/8 tsp ground cinnamon
¼ tsp fine sea salt
40 grams unsalted butter, slightly softened
85 grams egg whites
Seville orange marmalade
icing sugar, fresh fruit and/or walnut halves
Preheat the oven to 180 degrees. Put the walnuts for both the dough and the filling in separate baking tins and bake at 180 degrees until lightly toasted and fragrant. Leave to cool at room temperature.
Put the walnuts for the dough in a food processor with the icing sugar, salt and cocoa powder and process until the nuts are finely ground. Add the flour and process until the ingredients are thoroughly combined. Add the chunks of butter and process until the butter is in very small pieces. Transfer the ingredients to a large mixing bowl. Whisk the eggs with the vanilla extract, add it to the bowl and quickly mix the ingredients together to form a cohesive mass. Knead the dough briefly in the bowl. The dough will be slightly more moist and stickier than usual, but it shouldn't feel too wet; if it does, mix in a little more flour. Divide the dough into four even pieces, shape them into a flat disc and wrap with a double layer of cling-film. Refrigerate for at least an hour.
For the tart, take one piece of dough from the fridge. It should be cold but pliable; if needed, let it soften slightly at room temperature. Roll it on a lightly floured work surface, adding more flour as needed to prevent it from sticking. Roll it into a large circle that's about 2.5mm thick. Carefully drape the circle of dough over a 24cm fluted tart pan with a removable bottom. Without stretching the dough, fit it into the contours of the pan. If the dough tears, just press it back together, adding scraps of dough, if needed. Reinforce the sides slightly by doubling over the dough and pressing firmly so the layers adhere, then trim off the overhang. Refrigerate the dough-lined pan for 30 minutes while pre-heating the oven to 200 degrees. Press a sheet of aluminium foil over the dough, fitting it into the contours of the pan. Bake at 200 degrees for 10 minutes then turn the heat to 180 degrees. Bake for 10 minutes then remove the layer of foil. Bake for five minutes, or until the surface of the dough is matte. Cool the tart shell to room temperature but leave the oven on.
Make the filling. Put the 160 grams of toasted walnuts in a food processor with the muscovado sugar, granulated sugar, cinnamon and salt and process until the nuts are finely ground. Use an electric mixer to beat the butter until soft. Add the nut/sugar mixture to the butter and beat until the ingredients are combined. With the mixer on low speed, add the egg whites. Increase the speed to medium high and beat for about five minutes, or until the mixture is light and fluffy. Occasionally scrape the beaters and the mixing bowl, to make sure the ingredients are evenly incorporated.
Spread a thin layer of Seville orange marmalade into the tart shell, then spread the walnut filling over the marmalade. Bake at 180 degrees for about 20 minutes, or until the filling is fragrant, matte and firm to the touch. Cool to room temperature. Dust lightly with icing sugar and decorate with walnuts and/or fruits of your choice before serving.