Herb Crusted Beef Tenderloin with Horseradish Sauce

untrimmed beef tenderloin (or 3-4 lb trimmed)

salt & pepper to season

grape seed oil

head of garlic, cut in half

bunch of fresh thyme (10-15 sprigs)

unsalted butter

chopped fresh parsley

chopped fresh basil

chopped fresh thyme

mayo

prepared horseradish

whole grain mustard

garlic clove, minced