Instructions

1. Preheat oven to 375°F. Boil potatoes in salted water until completely tender, 15–18 minutes. Drain, then mash with butter and warm milk until smooth. Season with salt and set aside.

2. While potatoes cook, heat olive oil in a large skillet over medium heat. Add onion and cook until soft, 5 minutes. Add garlic and cook 1 minute.

3. Add carrots, parsnips, and zucchini. Cook, stirring, for 5–6 minutes until beginning to soften.

4. Sprinkle flour over the vegetables and stir for 1 minute. Pour in broth gradually, stirring until a light sauce forms. Add thyme, rosemary, salt, and white pepper. Simmer 5 minutes until slightly thickened.

5. Pour the filling into a 9×13 baking dish. Spoon the mashed potato on top and spread into an even layer, using a fork to create gentle ridges.

6. Bake until the top is golden and the filling is bubbling at the edges, about 25–30 minutes. Let rest 5 minutes before serving.