Preheat the oven to 200°C / 392°F (top/bottom heat).
First, prep the veggies. Wash the cauliflower, remove the leaves, and cut it into small florets. Steam for about 7 minutes until tender but still firm (you don’t want them mushy, or they’ll fall apart when baking). PS: Don’t toss the leaves! Chop them up and save them for a soup or stew—they’re totally edible.
Wash and clean the leeks, making sure to rinse out any dirt between the layers. Slice them in half lengthwise, then cut into half-moons.
Place the sliced leeks and steamed cauliflower into a large baking dish.
For the sauce, press the garlic and mix it with all the other sauce ingredients. Pour it over the veggies in the baking dish.
Bake in the preheated oven for about 40 minutes, until the top is golden brown. Enjoy!