Dice all the vegetables – cut the onions, fennel, and carrot into ½″ pieces. You can combine them all into one large bowl.
Heat a large pot on medium high heat. Add 2 tablespoons of olive oil, then add the diced onions, fennel, carrot, and a big pinch of salt. Cook until tender (about 10 minutes), stirring occasionally.
Add in lentils, bay leaf, cinnamon stick, stock, and another big pinch of kosher salt. Bring to a boil, then reduce to a simmer and cook until lentils are soft (about 20 minutes).
Remove bay leaves and cinnamon stick, and blend about 2 cups of soup until smooth.
Add this puree back in, taste, adjust seasoning with salt and pepper, and serve!
