Torta Sbrisolona (Mantuan Crumbly Cake)
Sbriciolarsi. In Italian, this verb means 'to crumble' or 'to fall into pieces'. It may not sound very promising but I can assure you that this characteristic works to great effect in one my favourite cakes ever, lakeside Mantua's sbrisolona, meaning 'big crumbly one'. In this case, the crumbs are made of flour, polenta, sugar, roughly chopped almonds, butter and just enough egg yolk to keep the sandy and coarse bricioli bound together while baking.
It's generally thought that this shortbread-like fixture in Mantua's bakeries has its origins in the surrounding Lombard countryside. Peasants made a hard and crumbly dessert of sorts by mixing crushed grains such as millet and cornmeal, hazelnuts and lard. This modest treat was then enrichened by the cooks serving the city's ruling Gonzaga family in the 1600s with the luxurious (for the time) additions of almonds, butter, sugar and spices. Though it would be several centuries before these ingredients were readily available (and affordable) to much of the city and surrounding countryside's population, it was a cake many local, less well-off families worked hard to save up for and make on special occasions.
The formula for making sbrisolona is remarkably similar in all the recipes I've consulted. It's also easy to remember, with equal amounts of wheat flour, cornmeal, sugar, nuts and fats called for. It's becoming more and more common in contemporary recipes to replace the hazelnuts and pork-based strutto or lard once commonly used with almonds and butter. I, however, have opted to use both types of nuts and fats, all in equal amounts, in homage to this cake's humble yet aristocratic origins. Feel free to use whatever fat or nut you have on hand though, whether it's just butter (or lard) or just almonds (or hazelnuts). It will taste wonderful, regardless.
Preheat oven to 160 º C. Combine polenta, flour, almonds, hazelnuts, caster sugar, lemon zest (if using) and salt in a large mixing bowl. Add chilled butter and lard. Use your fingertips to work the butter and lard into the dry ingredients until you have a coarse, crumbly mixture. Form a well in the centre, add egg yolk, and using your hands, quickly mix until the crumbs clump together.
Grease and dust a 23 cm cake tin with butter and flour. Transfer the crumbly dough into the tin and distribute evenly inside it. Avoid the temptation to flatten the crumbs on the top – the surface should be rough, not smooth.
Bake the cake for 40-50 minutes, or until dry and golden brown on the surface. Remove from the oven and allow to cool completely. Serve broken into chunks, at the end of a long and lazy meal, to accompany a cup of coffee, a shot of grappa or a caffé corretto (coffee 'corrected' with grappa). Also works well with an Italian-style breakfast, dipped into a mug of caffè latte. Keeps well in an airtight cointainer for up to 5 days.