Bring a large pot of water to a boil. Add 180 g pasta and 1 tsp salt. Cook, following package instructions, until al dente. Drain the pasta once cooked, but be sure to reserve the pasta water (we'll use it later).
Heat 2 tablespoons olive oil in a large frying pan over medium flame. Add 2 cloves garlic (minced) and 20 g leek (white parts only, finely chopped). Sauté until aromatic.
Trim the woody ends from 125 g tenderstem broccoli and 125 g asparagus, then cut into large pieces. Also trim 80 g green beans, cutting them into pieces around an inch long.
Add all three vegetables to the frying pan and mix well with the aromatics. Cook until the garlic and leeks have lightly browned.
Next, add 150 ml reserved pasta water to the frying pan. Continue to cook the vegetables in the water for around three-five minutes. They should be tender, but retain some bite.
Stir in 125 g mascarpone and mix well.
Tip the drained pasta back into the pan and mix, so the pasta is completely coated in sauce. Add ½ tsp black pepper (Freshly cracked), 2 leaves mint (chopped), and 1 small handful parsley leaves (chopped).
Grate over 20 g pecorino. Add a little more pasta water if needed to loosen the consistency, and serve.
Notes
I don't add any salt to the finished creamy vegetable pasta, as salting the pasta water seasons the dish enough.