In a 4-qt. pot heat oil over medium heat. Add leeks. Cook, stirring occasionally, 5 to 7 minutes or until very tender but not browned (reduce heat if leeks begin to brown). Stir in chickpeas and garlic. Cook about 2 minutes, stirring occasionally.
Add stock and 1 cup water. Bring to boiling. Reduce heat. Add lemon juice. Simmer, uncovered, 5 minutes. Gradually stir in the spinach and thyme. Cook until the spinach is wilted, about 1 minute. Season to taste with kosher salt and black pepper. Serve immediately. Makes 4 servings.