French Onion Soup with Parmigiano-Reggiano-Crusted Sourdough Croutons

Yellow onions and leeks are mandoline-sliced and browned in a little butter with fresh thyme, bay and cracked allspice, then simmered in equal parts homemade chicken and beef bone broth, a little raw cider vinegar, sea salt and freshly-ground black pepper.  Served with Parmigiano-Reggiano-crusted sourdough croutons..

French Onion Soup with Parmigiano-Reggiano-Crusted Sourdough Croutons

3 medium yellow onions, peeled and quartered
1 medium leek, trimmed and rinsed free of dirt and sand
1-1/2 tablespoons cultured/pastured butter
1 teaspoon freshly-cracked allspice
2 small bay leaves
1 small bunch fresh thyme, stripped
3 cups homemade beef stock or broth
3 cups homemade chicken stock or broth
1/4 cup raw apple cider vinegar
sea salt and freshly-ground black pepper

2 slices sourdough boule, torn into 1-inch pieces
1-1/2 tablespoons cultured/pastured butter
2 tablespoons shredded Parmigiano-Reggiano

Combine beef and chicken broth in a heavy pot and bring to a rapid boil. Reduce heat to medium and allow to simmer until reduced in volume by about 25%.  Add vinegar, reduce heat to medium-low and keep hot.

Meanwhile, slice onions and leeks to about 1/8-inch thickness (a mandoline makes this easy) and add to a hot, dry skillet.  Stir often until onions begin to brown, then add butter, bay, allspice and thyme and continue to cook until onions are well browned, about 10-15 minutes.

Pour onion mixture into reduced stock and stir to combine.  Allow to simmer 10 minutes. Season to taste with sea salt and freshly-ground black pepper.

Meanwhile, saute torn sourdough in butter until golden brown on all sides.  Sprinkle croutons with Parmigiano-Reggiano and allow to melt and get a little crisp.  Remove from heat.

Ladle hot soup into bowls, dress with croutons and serve immediately.