Heat canola oil in a Dutch oven over medium-high heat; cook and stir onion, carrots, salt, black pepper, and sugar until onion is a deep brown color, 15 to 20 minutes. Reduce heat to medium; add garlic, chile pepper, ginger, and curry powder. Stir constantly to incorporate, about 5 minutes.
Increase heat to medium-heat and stir 1 can vegetable broth into the onion mixture. Scrape up any vegetables or curry powder stuck to the bottom of the pot with a wooden spoon.
Add lentils and remaining 1 can of vegetable broth; cook until lentils are tender, about 30 minutes. Stir cilantro into lentils before serving.
