Ingredients

Pastry:
1 1/4 cups all-purpose flour
1/3 cup ground almonds
1/3 cup confectioner's sugar
1 stick plus 1 tablespoon butter, cold and diced
1 egg, beaten
1 to 3 tablespoons iced water

Put the flour, almonds and confectioner's sugar into a food processor and pulse together. Add the diced butter and process again until the mixture resembles oatmeal. Or rub it by hand or mix in a standing mixer.
Beat together the beaten egg, salt and iced water, and tip down the funnel of the food processor as it is running to bind the pastry. Add more iced water if the pastry has not come together completely. The same goes for whatever method you're using. The almonds make this a wonderfully pliable, Play-Doh of a pastry.
Form the pastry into a flat disc, wrap in plastic wrap and leave to rest in the fridge while you make the filling.

Filling:
1 stick plus 1 tablespoon butter
1/2 cup plus 2 tablespoons superfine sugar
3 eggs
Zest and juice of 1 clementine
1/4 cups ground almonds
1 cup cranberry jam (recipe follows)
8 ounces royal icing mix
Few gold sugar stars or other decorations

Preheat the oven to 400 F.
Melt the butter, and leave it to cool slightly. Beat together the sugar, eggs and zest, and then add the melted butter. Stir in the ground almonds.
Roll out the disc of pastry to fit into a 10-inch, deep fluted tart pan with a removable base, and prick the base with a fork. Spread the jam onto the base of the pastry and pour over the almond mixture, taking care to cover all the jam.
Bake in the oven for 45 minutes. The filling will rise and look puffy in places, but once it comes out of the oven it will fall back again to form an even surface. Leave the tart to cool completely on a wire rack.
When the tart has cooled, slip the base out from the sides and sit it on a plate. Make up the royal icing mix with the juice from the clementine and as much water as you need to make a thick but spreadable icing; the clementine juice (though of course orange would work as well) makes the icing a very pleasing pale, peachy ivory. Work over the top of the tart and decorate as you wish. Makes 8 to 10 servings.

Cranberry jam:
4 cups cranberries
1 3/4 cups superfine sugar

Directions

Put a film of water in the bottom of a large saucepan and add the cranberries and sugar.

Stir patiently over a low heat to dissolve the sugar; this will take a little while. Turn up the heat and boil the pan rapidly until setting point is reached, about 7 minutes. (Alternatively it will have reached a jam-like consistency.)

Pour the jam into a sterilized 1 1/2-cup jar and seal immediately. Makes 4 cups.