Preheat oven to 375 degrees.
Melt 4 tablespoons of Country Crock® Spread over medium-high heat in large nonstick skillet and cook onion, stirring occasionally, until golden brown, about 8 minutes. Add crumbs; cook, stirring until lightly toasted, about 2 minutes; remove to bowl.
Melt remaining Spread in same skillet. Add Brussels sprouts; toss. Stir in half-and-half and 1/2 of the crumb mixture. Pour into shallow 2-quart baking dish. Sprinkle with remaining crumb mixture.
Bake 25 to 30 minutes or until bubbly around edges.