Step 2
Add 1/4 cup of the olive oil to a large frying pan and sauté the onions, carrots, celery, garlic, thyme and salt over medium- high heat, stirring frequently, for about 10 minutes, until the vegetables are tender and just beginning to brown. Add the tomato paste and continue to cook, stirring constantly, for 3 minutes. Add the mushrooms and cook, stirring frequently, for 15 more minutes, or until all the liquid is absorbed. Transfer the mixture to a large bowl and allow to cool to room temperature. When cool, add the lentils to the vegetable mixture.