Melt Country Crock® Spread in large skillet and cook onion and red pepper flakes over medium heat, stirring occasionally, until onion is tender, about 3 minutes. Stir in ground beef and 1/2 of the garlic and cook over medium-high heat, stirring occasionally, until ground beef is almost cooked, about 5 minutes. Stir in tomato, tomato paste and boiling water blended with Knorr® Vegetarian Vegetable Bouillon Cube. Cook over medium heat, stirring occasionally, until mixture starts to thicken. Stir in spinach and remaining garlic and cook, stirring occasionally, until spinach is wilted and ground beef is cooked.
Stuff peppers with ground beef mixture and arrange in medium baking dish. Bake uncovered 20 minutes. Top with cheese and bake an additional 5 minutes or until peppers are tender and cheese is golden.