French Lentil and Spinach Soup

olive oil

large yellow onion, finely diced

large or 2 smaller carrots, finely diced

small fennel bulb, finely diced ((or 1 large celery stalk))

garlic cloves, minced

prepared mustard ((I used stone-ground))

tomato paste

red wine

french green lentils de puy, optionally soaked for 4-8 hours

bay leaf

vegetable stock or water

salt and black pepper

loosely packed baby spinach leaves, washed

parmesan, for serving