STAGE 12: SAINT-JEAN-DE-MAURIENNE - ANNONAY DAVÉZIEUX

Another mountain stage, but perhaps a little less punishing that the previous stage. The peloton heads into the Ardeche region, famous for its rustic food and wine. The chestnut (châtaigne) is the pre-eminent foodstuff in this region, used to make marrons glaces (candied chestnuts) and many other dishes, including a sweet chestnut soup called cousina.

You can buy sweetened chestnut purée in cans or tubes in any French supermarket, and in some UK supermarkets (Waitrose keep it). When I was little, my mum often had a can of it in her larder, for making Mont Blanc (meringue topped with chesnut purée and cream) and as a filling for crèpes. It was a little taste of France before I ever visited the country, in a tin with Art Nouveau decorations (the tin hasn't changed much over the years!). Whenever I'm in France, I always buy chestnut purée in the supermarket.

Here's a recipe for a rich yet light, flourless chestnut cake that's easy to make - and even easier to eat!

Tarte de Purée des Chataignes
(Chestnut Puree Tart)
 
1 x 500g can sweetened chestnut purée
80g butter
5 eggs, separated
Dark chocolate to garnish

Grease and line a large deep 9-inch loose-bottomed cake tin.
Preheat the oven to 180°C / 350F.

• Melt the 80g butter in the microwave or on the stove. Set aside to cool slightly.
• Separate the eggs. In a large bowl, beat the egg yolks together with the chestnut purée until the mixture becomes light and thick (the goal is to beat as much air into the mixture as possible. Then, a little at a time, beat in the melted butter. Set aside.
• Beat the egg whites to the stiff-peak stage. Then add them to the egg yolk-chestnut purée mixture by spoonfuls and use a spatula to fold the whites carefully in.
• When the oven is ready, pour the batter into the tin and place gently in the oven. Don't bang the oven door, as the mixture at this point is more like a souffle than anything else. Bake for 25-30 minutes. Keep an eye on the browning of the top of the tart: you don't want it too dark. If this starts happening, carefully open and close the oven door to let some heat out: then lower the oven heat slightly and bake for a few minutes longer.
• The tart will puff up considerable while baking. Once removed from the oven, it will start to collapse. Don't panic, as this is normal. While still hot, use a very fine grater (a lemon-zest-size grater works well) to grate bitter baking chocolate over the whole top of the tart. It will melt onto the tart's top. You may want to do several layers of this.
• Allow the tart to cool. (If you like, you might want to drizzle melted chocolate over it.) Slice and serve with thick cream, whipped cream, pouring custard or a good-quality vanilla ice-cream.