Preheat oven to 375 degrees.

Place cauliflower florets in a steamer basket over boiling water. Cover pot and steam for 7 minutes until slightly tender. Drain and set aside.

Melt butter in a large saucepan over medium heat. Add garlic and cook for one minute.

Add flour and cook for an additional minute stirring constantly.

Slowly add milk and bring to a boil, stirring often until thickened.

Add salt, pepper, horseradish and all but 2 Tbsp. of the parmesan cheese.

Pour a little less than half of the sauce into the bottom of a casserole dish big enough to fit the cauliflower.

Add the drained cauliflower on top, followed by the remaining sauce.

Sprinkle with the panko bread crumbs, the remaining 2 Tbsp. parmesan cheese and some additional fresh ground black pepper.

Bake for 30 minutes until lightly browned.