Preheat your oven to 425°F. This high temperature is key to achieving that perfect roast.
Slice the head of the cauliflower in half from the top of the crown through to the stem. Be careful to cut evenly so they roast at the same rate. Remove the core of each half and discard the leaves.
Trim the cauliflower into florets. You can use your hands to break them apart or a knife for more precision. Aim for florets that are roughly the same size to ensure they cook evenly.
Scatter the florets on a high-sided baking sheet, making sure they are not overcrowded. Drizzle with olive oil and sprinkle with Italian seasoning, kosher salt, and black pepper. Toss everything to coat the florets evenly.
In a small bowl, mix together the Parmesan cheese, panko bread crumbs, and parsley. This mixture will be your crunchy topping.
Lay the florets on the baking sheet in a single layer, cut side down. This positioning helps them caramelize beautifully.
Bake in the preheated oven for 15 minutes. Keep an eye on them; you want them tender and starting to brown.
If you want them extra crispy, flip the florets halfway through the cooking time. This ensures all sides get that lovely golden color.
After 15 minutes, sprinkle the Parmesan mixture over the cauliflower and return to the oven. Bake for an additional 5 to 10 minutes, or until the cheese is melted and starting to brown.
Once done, remove from the oven and serve warm. Be sure to scrape up all the little crispy bits from the pan; they are a treat!