Heat olive oil in a large pot or Dutch oven over medium heat. Add the diced onion and sauté for about 5 minutes until softened.
Add the minced garlic, diced red bell pepper, and diced jalapeño. Sauté for another 3 minutes.
Stir in the tomato paste and cook for 2 more minutes, stirring frequently.
Add the fire roasted tomatoes, red lentils, black beans, corn, cashew cream, vegetable broth, chili powder, cumin, oregano, brown sugar, and salt. Stir well to combine.
Bring the soup to a boil, then reduce heat to low. Cover and simmer for 20–25 minutes, stirring occasionally, until lentils are fully tender and soft.
After 20 minutes, taste a spoonful to check the lentils. If still slightly crunchy, simmer an additional 5–10 minutes.
Carefully transfer 2 cups of soup to a blender and blend until completely smooth. Pour back into the pot and stir to combine. (Alternatively, use an immersion blender to partially blend the soup directly in the pot.)
Stir in the fresh lime juice. Taste and adjust salt, spice, or broth as needed.
Serve hot, garnished generously with tortilla strips, cilantro, avocado, lime wedges, and a dollop of cashew cream or vegan sour cream.