Heat the olive oil in a large sauté pan over medium heat until it shimmers and begins to gently ripple.
Add the finely chopped onion to the pan and cook, stirring occasionally, until it becomes translucent and fragrant, about 5 minutes.
Stir in the minced garlic and cook for about 1 minute, until fragrant and just starting to golden.
Add the grated carrots and diced mushrooms, stirring well. Cook for 8-10 minutes, until the vegetables soften, release their aroma, and the mushrooms begin to brown slightly.
Stir in the tomato paste and cook for 1-2 minutes, allowing it to deepen in color and become fragrant—this builds the umami base.
If using, pour in the red wine and let it simmer for 3-4 minutes until mostly evaporated, concentrating the flavors.
Add the crushed tomatoes, cooked lentils, and vegetable broth. Stir everything together, then add the bay leaf, thyme sprig, and smoked paprika, if using.
Bring the mixture to a gentle simmer, then reduce the heat to low. Cover partially and simmer for 30-40 minutes, stirring occasionally to develop deep flavors and thicken the sauce.
Remove the bay leaf and thyme sprig, then taste and adjust seasoning with salt and pepper. If you prefer a smoother sauce, blend a portion of it with an immersion blender until velvety.
Let the sauce rest off the heat for 5 minutes to allow flavors to meld, then serve hot over pasta, rice, or zucchini noodles. Garnish with fresh herbs if desired.
