Step 1 Sort over the lentils to remove any stones. Rinse well under cold running water. Place in a small saucepan. Stud the shallot with the cloves and add it to the lentils along with the carrot and pancetta. Add water to cover by 3 inches and bring to a boil. Reduce heat to low and simmer, stirring often, until the lentils are tender but still firm, 17 to 25 minutes. Drain well. Discard the carrot and shallot with cloves. Cut the pancetta into fine dice and set aside.
Step 2 Heat the oven to 400 degrees. Place the chicken stock in a small saucepan over high heat and cook until reduced by half. Add the rosemary and cream, lower the heat and simmer until thickened to sauce consistency, about 15 minutes. Strain, discarding rosemary. Season with salt, pepper and cayenne to taste.
Step 3Heat 2 tablespoons oil in a large nonstick skillet over medium-high heat. Season the sole well with salt and pepper. Place it in the pan, flesh side down. Cook 2 minutes, then turn it over and cook another 1 to 2 minutes, until barely pink in the center.
Step 4While the fish cooks, heat the remaining oil in a small skillet over medium-high heat. Add the pancetta and fry until crisp, then stir in the lentils and heat through.
Step 5Lay each piece of cooked sole on a serving plate. Distribute lentils along one side. Spoon rosemary cream thickly over the lentils and around the fish and serve at once.