With cannellini beans, broccolini, and plenty of veggies, this one-pan meal checks all the boxes.
In a large deep skillet, heat the oil over medium. Add the onion and carrot; season with salt and pepper. Cook, stirring often, until the vegetables begin to soften, about 5 minutes. Add the sausage; cook, stirring and breaking up the meat with a spoon, until browned, about 7 minutes. Add the garlic; cook until golden, about 1 minute.
Add the tomatoes with juices and 2 1/2 cups water. Bring to a boil. Add the pasta and broccolini stems. Cook, stirring occasionally, until the pasta is almost al dente, about 8 minutes.
Reduce heat to medium. Add the broccolini florets and beans. Cook until the broccolini is tender, 2 to 3 minutes; season.
Divide the pasta among bowls. Top with the mascarpone.