Place the chopped oranges in a small saucepan. Add 1 tablespoon water, then cover the pan and simmer gently for 30 minutes or until the oranges are soft and all the excess liquid has evaporated. Leave to cool.
Preheat the oven to 350ºF (180ºC). Line the bottom and sides of a 23 cm (9 in.) springform cake pan with parchment paper. Finely chop the oranges in a food processor or blender, or with a sharp knife.
Place the egg whites in a large bowl and beat with an electric mixer until they form stiff peaks. Gradually add half the caster sugar, then beat for 1 minute.
Place the egg yolks and the remaining caster sugar in another bowl and, using the same beaters, beat for 2–3 minutes or until pale and quite thick. Add the oranges and beat to combine well. Carefully fold in the ground almonds with a large metal spoon.
Stir in 3 spoonfuls of the egg whites to loosen the mixture, then gently fold in the remaining whites. Transfer the mixture to the pan and level the surface. Sprinkle with the flaked almonds.
Bake for 50–55 minutes or until the orange and almond cake is golden and a skewer inserted in the centre comes out clean. Check the cake after 20 minutes and again at 30 minutes, and cover lightly with aluminum foil if it is browning too quickly.
Leave the cake to cool in the pan, then turn it out, peel away the lining paper and transfer to a serving plate. Dust with icing sugar before serving. The Spanish orange and almond cake can be kept in an airtight container for up to 2 days.
Spanish orange and almond cake variations: This cake is delicious served with a mixture of 2⁄3 cup whipped, reduced-fat cream and 150 g ricotta cheese. • Instead of ground almonds alone, use a mixture of 1 1⁄4 cups each of ground almonds and semolina or instant polenta. Because this cake will be a little drier, drizzle over 2–4 tablespoons Grand Marnier, Amaretto liqueur or freshly squeezed orange juice rather than dusting with icing sugar.
Per serving: 275 calories, 8 g protein, 17 g total fat, 2 g saturated fat, 108 mg cholesterol, 24 g total carbohydrate, 24 g sugars, 3 g fibre, 30 mg sodium
Using whole oranges boosts the fibre and vitamin C content of this cake. Studies have shown a connection between a regular intake of vitamin C and the maintenance of intellectual function in elderly people. Also, this cake is suitable for those on gluten-free or wheat-free diets as it is made without flour.