Creamy ham and mushroom pasta

Name: Creamy ham and mushroom pasta
Prep time: 10 min
Cook time: 15 min
Total time: 25 min
Cuisine: Italian, European
Ingredients: 400g penne rigate; 1/2 onion, finely chopped; 250g button mushrooms, thinly sliced; 1 garlic clove, crushed; 5 slices ham off the bone, sliced; 375ml evaporated milk; 1 teaspoon cornflour; salt and cracked black pepper; 1 tablespoon finely chopped flat-leaf parsley; 1 tablespoon finely grated parmesan; salad leaves, to serve