Bring a large pot of salted water to a boil over high heat. Add the macaroni and cook for 2 minutes less than the package directions, 3 to 4 minutes. Drain well.
Heat the olive oil in a large straight-sided skillet over medium-high heat. Add the ground sirloin and sausage and cook, breaking up the meats with the back of a wooden spoon, until cooked through and browned, 6 minutes. Stir in the shallots and garlic; cook 2 minutes. Deglaze with the tomato puree, add 1/2 teaspoon salt and stir to combine. Reduce the heat to medium and simmer for another 4 minutes.
Add the macaroni to the sauce, sprinkle the bare pasta with the Parmesan and mix well. Stir in the mascarpone and spinach and cook an additional 3 minutes, until the sauce is creamy and the spinach wilted.