Cook pasta 1 min shy of al dente, according to instructions on package.
When pasta is cooked, drain and drizzle with olive oil to prevent sticking. Set aside.
Preheat oven to 350. Lightly grease the inside of baking dish.
In stockpot or dutch oven, melt butter over medium heat.
Whisk in flour and continue whisking until roux is bubbly and golden.
Slowly whisk in half and half until smooth.
Continue whisking until you see bubbles on the surface.
Whisk in salt and pepper
Add 2 cups of cheese and whisk until smooth.
Add another 2 cups of cheese and continue whisking until smooth. Sauce should be thick.
Remove from heat.
Add pasta into sauce and stir until fully coated.
Pour half of pasta into baking dish.
Pour remaining 2 cups of cheese on top of pasta in baking dish.
Top with remaining half of pasta.
In a small bowl, combine breadcrumbs, Parmesan cheese and melted butter.
Sprinkle breadcrumb topping over mac and cheese in baking dish.
Bake for 30 mins until bubbly and golden brown.
Serve immediately.