Heat oven to 400°. Slice off top 1/4 of garlic head, exposing tops of cloves. Place on a piece of aluminum foil and drizzle with oil, 1/4 tsp of the salt and freshly cracked pepper. Wrap in foil and roast at 400° for 1 hour, until softened.
In a skillet, melt butter over medium heat. Stir in flour; cook for 1 minute. Whisk in stock and heavy cream and squeeze in cooked garlic cloves (discarding skin). Bring to a boil. Simmer 8 to 10 minutes, until thickened. Stir in remaining 1/4 tsp salt and more freshly cracked pepper.