Boil pasta in salted water until al dente, about 8-10 minutes. Reserve 1/4 cup pasta water, then drain.

In a large pan over medium heat, melt butter with olive oil. Add minced garlic and cook 30 seconds until fragrant.

Stir in gochujang paste and cook 1 minute until toasted.

Pour in heavy cream, simmer 2-3 minutes until thickened. Off heat, stir in parmesan until melted. Add pasta water if needed.

Add drained pasta, toss to coat. Season with salt and pepper. Garnish with green onions and sesame seeds. Serve hot.