Melt butter with olive oil over medium heat. Add garlic and cook 2 to 3 minutes until fragrant and just pale gold. Do not brown fully.
Add broth, cream, onion powder, red pepper flakes, and salt. Stir and bring to a gentle simmer over medium-high heat.
Add dry pasta directly to the simmering liquid. Press down with tongs to submerge. Cook uncovered over medium heat, stirring every 2 minutes, for 10 to 13 minutes until al dente and sauce is glossy and coating. Add water in small splashes if the pan looks dry before pasta is done.
Remove from heat. Add parmesan and stir vigorously until fully melted and smooth. Season with salt and pepper.
Plate immediately and top with fresh parsley, extra parmesan, and cracked black pepper.