1. Preheat oven to 400°F.
2. Fill a large 8 quart sauce pan with water, cover and bring to a boil.
3. Meanwhile, in a medium sauce pan (about 4 quarts) over medium heat, melt 4 Tbsp butter, add flour, Italian seasoning, garlic powder and nutmeg. Whisk for 2 to 3 minutes to cook out the "flour-y" taste. Add milk, whisk to combine. Allow to cook until pasta water comes to a boil.
4. Add a handful of salt to boiling pasta water. Cook pasta to al dente; meaning it still has a little bite to it (approximately 7 minutes). Al dente pasta absorbs sauce better while it cooks and this is going into the oven.
5. Add Parmesan cheese to sauce and stir. Sprinkle in Italian cheese blend, stirring until the cheese sauce is smooth. Reduce heat to simmer.
6. Meanwhile slice grape tomatoes in half lengthwise. Drain sun-dried tomatoes. In a microwave safe bowl, add butter and microwave until melted. Add bread crumbs and combine with a fork until butter is absorbed into bread crumbs. Add ½ cup Parmesan cheese and stir with fork until combined. Set aside.
7. Once pasta is drained and returned to the hot pan, add sun-dried tomatoes and grape tomatoes (reserving 10 or so for garnish). Stir. Pour in cheese sauce, reserving about 1 cup. Stir until combined.
8. Pour pasta into a baking dish and smooth out with spoon. Pour remaining cheese sauce evenly over top. Sprinkle with bread crumb topping. Garnish with reserved tomatoes. Place baking dish on a cookie sheet and bake for 5-7 minutes until topping is golden brown. Serve and enjoy!