Cook pasta according to package directions, omitting salt and fat. Drain and transfer to a large bowl; keep warm.

Melt butter in a small skillet over medium heat; swirl to coat. Add panko to pan; cook 3 minutes or until browned, stirring frequently.

Heat olive oil in a cast-iron skillet over medium heat until the oil shimmers, and cook garlic, stirring often, until golden brown and fragrant, about 3 minutes. Stir in onion and cook until soft, stirring often, about 5 minutes. Add Brussels sprouts to the skillet and cook without stirring until the undersides of the sprouts turn golden brown, 5 to 7 minutes. Stir to turn sprouts over, and cook other sides until golden brown, another 5 to 7 minutes.

Add broth and next 6 ingredients (through crushed red pepper). Cover and cook 2 minutes or until Brussels sprouts are crisp-tender. Add Brussels sprouts mixture to pasta; toss well. Sprinkle with cheese, pine nuts, and panko. Serve immediately