Our local town, Certaldo, had been famous for almost a thousand years for its delicious red onions. In the last few years a group of local farmers, supported by the Slow Food Foundation and the City Hall has been growing them and popularising them again. They are used in many dishes; one of the most popular is this simple, warming soup.
4 large red onions (mild if possible), approx 1 kg, ½ lb
Vegetable stock , 1 litre (1 quart)
1 medium potato, peeled and cut into half inch cubes
Extra virgin olive oil
Rustic style bread (sourdough is good)
Peel the onions and slice them.
Add to 2 tablespoonfuls of cold extra virgin olive oil in a pot and soften on a low-medium heat, moving around so that the onions do not burn. Cook until some are golden (10 minutes approx).
Add the hot vegetable stock and the potato. If the stock is unsalted, add half a teaspoon of salt. The stock should easily cover the vegetables. If it does not, boil water and add until they are well covered.
Cook with the lid on the pot on a medium heat until the onions and potatoes are very soft. Make sure that the liquid level is always covering the vegetables. Add more boiling water if necessary. (20-30 minutes). Turn off the heat.
Either sieve the soup or use a hand-blender to blend it. Either way, you will get a smooth creamy soup.
Serve with slices of toasted rustic bread, a good drizzle of extra virgin olive and plenty of freshly ground black pepper.