►Cook penne pasta according to package instructions and cool. Meanwhile, heat oven to 375°F.
►Heat olive oil in a medium skillet set over medium-high heat. Add diced onion. Cook until translucent, stirring occasionally, about 5 to 7 minutes.
►Add garlic to skillet and stir. Add ground Italian sausage and break up with a wooden spoon. Add salt, pepper, and cumin and cook until sausage has browned, about 8 to 10 minutes.
►Melt butter in medium saucepan set over medium heat. Sprinkle in flour and stir with a wooden spoon to make a roux. Cook for 1 to 2 minutes, or until golden. Add milk and whisk constantly, bringing mixture to a gentle simmer. Reduce heat to medium-low and continue whisking until sauce has thickened, about 2 to 3 minutes. Remove from heat and add Taleggio and 4 ounces of parmesan. Whisk until cheeses melt.
►Add sausage mixture, frozen peas, and Taleggio sauce to reserved pasta. Toss to combine. Pour pasta into a 9-inch-by-13-inch baking dish and top with remaining parmesan. Bake pasta for 20 minutes or until parmesan is golden brown.