Heat olive oil in a heavy-bottomed pan over medium heat until it shimmers and you hear a gentle sizzle.
Add the finely chopped onion and cook, stirring frequently, until it becomes translucent and fragrant, about 5 minutes.
Stir in the minced garlic and cook for about 1 minute until it releases a pungent aroma, being careful not to burn it.
Add the diced carrots and chopped celery, stirring well. Cook until they soften slightly and develop a sweet aroma, about 8 minutes.
Pour in the rinsed lentils and stir to coat them in the aromatics and oil, cooking for 2-3 minutes until fragrant.
Add the vegetable broth and tomato paste, stirring to combine. Let the mixture bubble gently for 2 minutes to meld flavors.
Stir in the crushed tomatoes and dried oregano, then bring to a gentle simmer. Lower the heat to medium-low, partially cover, and cook for 30-40 minutes, stirring occasionally.
Check the lentils; they should be tender and starting to break down, creating a thick, rich sauce. Adjust seasoning with salt and pepper as needed.
Once done, remove from heat and let the sauce rest for about 5 minutes to deepen the flavors.
Cook your favorite pasta until al dente according to package instructions, then drain.
Serve the lentil Bolognese over the cooked pasta, garnished with fresh basil leaves. Drizzle with a little olive oil and enjoy this hearty, plant-based dish.