2 tablespoons olive oil
1 leek, white and light green parts only, chopped
6 cups chicken stock or canned low-sodium broth
1 cup ditali or other small pasta
Salt
10 pencil-thin asparagus, cut into 1-inch lengths
1 small fennel bulb, cored and cut into 1/2-inch dice
1/4 pound sugar snap peas, halved crosswise
1 cup coarsely chopped Swiss chard leaves
One 15-ounce can cannellini beans, drained and rinsed
1/2 pound thawed frozen peas
2 tablespoons chopped mint
Freshly ground pepper
1/2 cup freshly grated Parmesan cheese