Preparation Melt butter with oil in heavy large Dutch oven over medium-high heat. Add asparagus and sauté 3 minutes. Using slotted spoon, transfer asparagus to bowl. Add onions and garlic to Dutch oven. Sauté until light golden, about 10 minutes. Add tomatoes with their juices, oregano and crushed red pepper. Bring sauce to boil. Reduce heat to medium and simmer until sauce thickens slightly, breaking up tomatoes with back of spoon and stirring occasionally, about 15 minutes. Return asparagus to sauce. Cook until asparagus is crisp-tender, about 3 minutes. Add penne and 1/2 cup cheese. Toss to combine. Season with salt and pepper. Transfer pasta to large bowl. Serve, passing additional cheese separately.
Preparation Melt butter with oil in heavy large Dutch oven over medium-high heat. Add asparagus and sauté 3 minutes. Using slotted spoon, transfer asparagus to bowl. Add onions and garlic to Dutch oven. Sauté until light golden, about 10 minutes. Add tomatoes with their juices, oregano and crushed red pepper. Bring sauce to boil. Reduce heat to medium and simmer until sauce thickens slightly, breaking up tomatoes with back of spoon and stirring occasionally, about 15 minutes. Return asparagus to sauce. Cook until asparagus is crisp-tender, about 3 minutes. Add penne and 1/2 cup cheese. Toss to combine. Season with salt and pepper. Transfer pasta to large bowl. Serve, passing additional cheese separately.