Preheat oven to 350 degrees. Lightly butter a deep 2 1/2 quart casserole dish.
In a large saucepan over high heat, bring salted water to a boil, add oil and cook noodles until tender, about 7 minutes. Don't overcook, drain well, return noodles to cooking pot.
In a microwave safe dish, melt 1 1/2 sticks butter, then mix butter into noodles. In same butter bowl place milk, 1/2 cup half and half cream and Velveeta and melt in microwave. Lightly beat egg and add it to noodles first mixing well and then add melted cheese mixture. Mix in all the shredded cheeses except 1/2 cup of sharp cheddar. Add the rest of half and half, blend and pour into casserole dish.
Cover top with 1/2 cup sharp cheddar cheese and dot with remaining 1/4 cup butter. Bake until it's bubbling around edges, about 25 to 30 minutes. Serve hot. Makes 6 to 8 servings. Enjoy!