Follow these step-by-step instructions to prepare your delicious lentil soup:

1. Heat the Oil
   In a large pot, heat a splash of olive oil over medium heat.
2. Sauté Onion and Garlic
   Add the chopped onion and minced garlic to the pot. Sauté until the onion becomes soft and translucent, releasing its aromatic essence. This should take about 3-4 minutes.
3. Add Carrots and Celery
   Stir in the diced carrots and celery. Cook for an additional 5 minutes, allowing the vegetables to soften slightly while absorbing the flavors of the onion and garlic.
4. Incorporate Lentils and Broth
   Introduce the rinsed lentils, vegetable broth, and canned diced tomatoes into the pot. Stir well to combine all ingredients.
5. Season the Soup
   Add the thyme, salt, and pepper to taste. Adjust the seasoning according to your preference for a perfectly balanced flavor.
6. Simmer the Soup
   Bring the mixture to a gentle boil. Once boiling, reduce the heat to low and let it simmer for 25-30 minutes. During this time, the lentils will absorb the flavors and become tender.
7. Serve and Enjoy
   Once the lentils are cooked to perfection, your soup is ready to be served. Ladle the warm soup into bowls and relish each comforting bite.