Prepare the sautéed vegetables: cut the onion, celery, and carrot into small pieces.
In a pan, heat the oil along with the bay leaves.
Add the onion, the celery, and then the carrots and stir well.
Sauté over medium-high heat; be careful as the onion shouldn’t get too brown.
Add the tomato paste and then the tomato sauce.
Cook for a few minutes allowing the flavors to meld together.
Add the lentils and stir well with a wooden spoon. Cook for about 15 minutes.
Reduce the heat to low and cover with a lid.
Season with salt, pepper, and red pepper flakes.
In another pot bring the water to a rolling boil.
When the water boils, add a generous handful of coarse salt; then add the pasta and cook according to the package instructions.
Drain the pasta and add it into the lentil sauce.
Stir well to combine, cook for a couple of minutes over high heat, and serve hot. It is ideally paired with a crisp green salad.