Step 1Heat the oil and butter in a saucepan over medium heat. Chop the onion and add it to the pan. Cook, stirring occasionally, until the onion has softened, about 6 to 8 minutes.
Step 2While the onion cooks, peel and thinly slice the carrots, cut the broccoli into florets (if the florets are large, cut them in half), cut the zucchini in half lengthwise and then cut it in 1/2-inch slices. Mince the garlic.
Step 3Add the flour to the pan and cook, stirring, until it forms a paste, about 2 minutes.
Step 4Add the carrots, broccoli, zucchini, garlic and mushrooms to the pan. Cook, stirring, about 3 to 4 minutes.
Step 5Add the thyme, vegetable broth and salt and pepper to taste.
Step 6Cook, stirring occasionally, until the vegetables are just tender and a gravy has formed, about 15 minutes. Serve over brown basmati rice and garnish with the chopped parsley.