In a food processor, pulse the onion, carrot, and celery until finely minced. Alternatively you can use a grater or mince finely with a knife.
In a dutch oven, heat 1 tablespoon of the olive oil on medium heat. When the oil starts to shimmer, add the minced carrot, celery, and onion. Sauté for 3-4 minutes until soft. Push the veggies to the side and add 1 more tablespoon of olive oil. To the oil add the crushed garlic and pepper flakes. Sauté in the oil for about a minute until the garlic becomes fragrant. Add the tomato paste and stir everything together.
Add the water and use your spoon to deglaze and bits stuck to the bottom of the pot. Add in the crushed tomatoes, dried herbs, and dry lentils. Stir everything together. Bring the mixture to a simmer on low-medium heat and cover. Simmer for about 20 minutes until the lentils are cooked. Every 5 minutes or so, stir the sauce and add more water if the sauce appears to be too thick for the lentils to absorb any moisture.
When the lentils are cooked the sauce should be nice and thick. If the sauce needs to thicken more, uncover and let simmer for a few minutes. Serve with the pasta of your choice.
If you don’t have a garlic press, you can process the cloves in the food processor separately from the veggies. Or mince finely with a knife.