Bring a large pot of lightly salted water to a boil. Add penne and cook until al dente, 8 to 10 minutes and drain. Meanwhile, heat the olive oil in a large skillet over medium heat. Stir in the garlic, prawns and turned translucent, about 5 minutes. Pour in the white wine, and simmer for 2 minutes. Stir in the chilli flakes (optional ), herbs butter, and asparagus; cook until the asparagus is just tender, about 3 minutes. Add cream, continue cooking until the shrimp have turned pink and are no longer translucent in the center. Season to taste with salt and pepper. Toss the cooked penne pasta with the prawns and asparagus mixture. Sprinkle with parsley.