Add the chicken stock, cream and 3/4 cup parmesan cheese and stir to combine. Add the lemon juice. Bring to a simmer and allow the sauce to cook down, till thickened slightly. Stir regularly. Season with salt and dried chilli flakes if using.
Vegetable options
Green beans, broccoli, broccolini, leeks, sweet peas, sugar snap peas, baby spinach, kale, asparagus etc.
Cut any that require it into bite sized pieces. The sweet peas (like from a bag of frozen peas) and the baby spinach really don't need cooking, so these can be added directly into the sauce when stirring in the cooked pasta and other vegetables.