Cook bowtie pasta in salted boiling water according to package directions until al dente, about 10-12 minutes. Drain and set aside without rinsing.
Heat olive oil in large skillet over medium heat. Add diced onion and cook for 2-3 minutes until translucent and lightly golden. Add minced garlic and cook for 30 seconds until fragrant.
Add ground beef to skillet and break apart with spatula. Cook for 5-6 minutes until completely browned, letting it sit undisturbed briefly to develop caramelized bits.
Stir in beef broth to deglaze pan, scraping up browned bits. Add red pepper flakes if using, salt, and black pepper. Simmer for 3-4 minutes until broth reduces slightly.
Add cooked pasta to skillet and toss to coat. Drizzle with extra olive oil if needed for gloss.
Plate pasta and sprinkle with freshly grated Parmesan and chopped parsley. Add extra cracked black pepper to finish.
Notes
Use 80/20 ground beef for best flavor and moisture. Leaner beef works but add extra olive oil.
Don’t rinse pasta – surface starch helps sauce cling better.
Let beef sit undisturbed briefly while browning for caramelized bits that add depth.
Flavors deepen as it sits, making leftovers excellent.