Set a large, heavy-bottomed pot on the stove over medium heat. Once it’s hot, pour in the olive oil.
Add the diced onion and cook until very soft and translucent, about 5-6 minutes. If onions are browning too fast, lower the heat.
Add the garlic and red pepper flakes (if using) and stir for 30 seconds. Add the tomatoes and roasted red peppers. Season with salt and pepper. Keep sautéing until the tomatoes start to break down, about 3-4 minutes.
Add the red lentils and vegetable stock and stir. Bring the mixture to a boil and then lower the heat to a simmer. Pop a lid on top and continue to simmer until lentils have fully cooked, about 18-20 minutes.
Once the lentils are soft, add the tahini. From here, use a stick blender to get the soup to your desired consistency. I like it mostly smooth, thick, and with a bit of texture. Add more stock if you’d like a more fluid texture. Then, stir in the lemon juice and basil.
Taste the soup for seasoning and adjust if necessary (more salt, more lemon etc).
Serve the soup hot with accompaniments!
Equipment
Stick Blender
Recipe Notes
I use roasted red peppers from a jar for maximum ease. If you don’t mind an extra step, you can certainly roast them yourself!
I like to leave a little texture in this soup, so prefer using a stick blender. You can use an upright blender if you’d like it silky smooth!
If you use all grape/cherry tomatoes, you don’t need to cut them, which makes the prep a little faster.
Depending on your tomatoes, you may not need much lemon juice at all. I would taste the soup right after blending to get a feel for where the acidity is at, and then proceed from there.
A quick blitz with a stick blender gives this red lentil tomato soup a lush, super creamy body with just a bit of texture left in for interest. Ready in about 40 minutes with smoky roasted red peppers and basil.