• Heat the olive oil in a large pot or Dutch oven over medium heat.
• Add the onion and garlic, and sauté until fragrant and translucent, about 2-3 minutes.
• Add the carrots, celery, and bell pepper, and sauté for another 5-7 minutes, until the vegetables are slightly softened.
• Add the diced tomatoes, tomato paste, thyme, oregano, smoked paprika, salt, and pepper, and stir to combine.
• Add the lentils and vegetable broth, and bring the mixture to a boil.
• Reduce the heat to low, cover the pot with a lid, and simmer for 30-40 minutes, or until the lentils are tender and the vegetables are fully cooked.

Instant Pot:

• Combine all the ingredients in the pot and cook on high pressure for 20 minutes. Allow for a natural release.
• Serve the stew hot, garnished with fresh parsley if desired.