1 large head of cauliflower, cut into florets
3 tablespoons unsalted butter
1 medium shallot, diced (about 1/4 cup)
3 tablespoons flour
1/2 teaspoon freshly ground white pepper
1/2 teaspoon ground nutmeg
1/2 teaspoon ground cumin
2 1/4 cups whole milk, warm
1/4 cup heavy cream
3/4 cup grated pecorino Roman cheese, divided
1 1/2 teaspoons kosher salt
1/2 cup panko-style bread crumbs
2 tablespoon melted butter
2 tablespoons roughly chopped fresh parsley leaves