Heat the oil and/or butter in a heavy bottomed skillet. Stir in the onions and cook over medium heat, stirring occasionally, until the onions are very soft and turning brown. This will take time—at least 45 minutes. If the onions start to brown too quickly, turn down the heat; don’t hurry their caramelization. Stir in the garlic in the last 10 minutes, after you see some hints of brown onion.

Deglaze the pan with the tequila, stirring it around. Transfer to a saucepan or small soup pot. Add the vegetable stock, the chickpeas and the bay leaves. Bring to a boil, lower the heat, and simmer for 15 minutes or so.

While the soup is cooking, toast some slices of baguette and slather them with basil pesto. Set aside.

In a small bowl smooth the miso paste with water. Just before serving, fish out the bay leaves and stir the miso into the soup. Season with salt, if needed, and plenty of freshly ground black pepper.

Ladle the soup into bowls, slipping a few pesto croutons into each bowl.