Heat olive oil in a large, deep skillet over medium heat. Add the diced onion and cook for 4 to 5 minutes, stirring occasionally, until soft and translucent.

Add the minced garlic, smoked paprika, cumin, and red pepper flakes. Stir and cook for 60 seconds until fragrant.

Add the diced zucchini and red bell pepper. Cook for 3 minutes, stirring occasionally, until the edges begin to soften slightly.

Pour in the canned diced tomatoes, rinsed green lentils, and vegetable broth. Stir everything together and bring to a boil.

Reduce the heat to medium-low, cover with a lid slightly ajar, and simmer for 20 to 22 minutes until the lentils are tender but still holding their shape. Stir once halfway through and check for liquid - add a splash of broth if the pan looks dry.

Remove the skillet from heat. Stir in the baby spinach and fresh basil until the spinach wilts from the residual heat, about 90 seconds.

Add the lemon juice, salt, and black pepper. Taste and adjust seasoning, then serve immediately.