Cauliflower Mascarpone Gratin

The last time I made this recipe, I used the very colorful cheddar and romanesco cauliflowers. Love those fractals!

This recipe was from Family Style Food. Here's the text, in case the link goes bad. My updates in italics.

CAULIFLOWER MASCARPONE GRATIN

1 large head cauliflower (3 pounds) separated into florets (8 cups)
1 tablespoon softened butter
1 8-ounce container mascarpone cheese (I have tried cream cheese, it is much heavier)
1/2 cup heavy whipping cream
1 tablespoon all-purpose flour
½ cup grated Parmesan cheese
2 tablespoons chopped fresh sage, rosemary or thyme (or a combination) (dry is just fine)
1 garlic clove, grated on a rasp grater or pressed in a garlic press
1 teaspoon kosher salt (I would use less)
panko bread crumbs

Blanch the cauliflower in a pot of boiling salted water 5 minutes (I cook it in a steamer). Drain well. Heat oven to 400 degrees. Coat a 3 -4 quart shallow gratin or baking dish with the butter. Put the cauliflower in the dish. In a medium bowl, whisk the mascarpone, cream, flour, ¼ cup of the Parmesan, herbs, garlic and salt until smooth (I have trouble with the whisking so I heat the mascarpone in the microwave until it's quite soft). Spoon the mixture over the cauliflower. Sprinkle the top with the remaining Parmesan. I sprinkle bread crumbs on top. Bake 30 minutes, or until top is browned and sauce is bubbling. Rest 15 minutes before serving. The creamy sauce will thicken a bit as it cools. 4-6 servings.