Begin by chopping the carrots, onion, and celery into small, even pieces. Rinse the French lentils under cold water until the water runs clear.

In a large pot, heat a couple of tablespoons of olive oil over medium heat. Add the chopped onions, carrots, and celery, stirring occasionally. Sauté the vegetables for about 5-7 minutes until they soften.

Stir in the rinsed lentils, diced bacon, thyme, and bay leaf into the softened vegetables. Pour in your choice of broth, bringing the mixture to a gentle boil.

Once boiling, reduce the heat to low, cover the pot, and let the soup simmer for 30-35 minutes, ensuring it stays at a gentle simmer.

After simmering, taste the soup and adjust the seasoning with salt and pepper. Remove the bay leaf before serving, and ladle the soup into bowls.