In a large pot, heat oil over medium-high heat, sauté onions until softened, about 5 minutes. Add garlic and tomato paste and cook until tomato paste begins to caramelized, about 2–3 minutes.
Add broth, spices and kale. Bring to a boil and reduce to a simmer, simmer until kale is tender, about 10–15 minutes. Gently stir in beans.
Mix cornmeal and water into a slurry and while stirring slowly pour into simmering stew. Simmer for 15 minutes.
Turn off heat and add lemon juice and zest, to taste.