Heat 1 tablespoon oil over medium heat in a cast iron pan until shimmering. Add the sausage, breaking it apart with a wooden spoon, stirring until only a little pink remains, about 3 minutes. Place sausage in a bowl and set aside.
In the same pan over medium heat, add remaining oil and heat until shimmering. Add the shallot and a pinch of salt, stirring until softened, about 2 minutes. Add the cumin, scraping up any bits of browned sausage at the bottom of the pan, and cook until fragrant, about 30 seconds more.
Pour in the tomatoes and stock, breaking the tomatoes apart with a wooden spoon once softened. Adjust heat to maintain a simmer, then add the lentils. Season with salt and pepper. Cook until softened, about 30 minutes, or until lentils are tender to the bite.
Adjust broiler rack to 6 inches below the heating element and preheat broiler to high. Stir in the sausage and kale, until wilted. Place pan under the broiler until sausage is browned, about 4 minutes. Top with parsley and serve with crusty bread, if desired.