Preheat your oven to 190° C (375° F). Grease a 4 quart shallow baking dish with butter.
Place garlic on a 10 inch piece of foil, drizzle with the oil and crimp the foil closed.
Place on a baking sheet and bake for 30 minutes or until tender. Allow the garlic to cool for 15 minutes. Cut the head in half and squeeze out the cloves into a small bowl. Mash into a smooth paste.
While the garlic is roasting, cook the pasta in a pot of boiling salted water until just tender, then drained and cooled under running water to stop the cooking process. Place the drained pasta in a large mixing bowl.
Microwave 2 tablespoons of butter in a medium bowl until melted, stir in 1/4 teaspoon salt until the salt is dissolved. Stir in the panko until well blended. Set aside.
Add remaining 4 tablespoons of butter to a medium saucepan and melt. Add the flour, stir, and cook until light brown in color.
Stir in the garlic paste, remaining 1 teaspoon of salt and the black pepper. Remove from heat.
Whisk the cheese into the saucepan, 1/2 cup at a time, until melted and smooth.
Pour the cheese sauce into the large bowl with the pasta, stir to mix together.
Transfer the pasta to the prepared baking dish and spread out evenly. Sprinkle evenly with the panko mixture.
Bake 40 minutes or until bubbly and topping is golden brown. Let stand 10 minutes.
Serve as a side with any main dish. Enjoy.