Bring large pot of salted water to boil. Add noodles and cook until just tender. Drain and set aside.
In large pot over high heat, melt butter then saute diced apple until caramelized and tender. Sprinkle in flour and stir. Cook 1 minute, stirring frequently.
Whisk in heavy cream and milk; bring to boil, whisking frequently so milk doesn’t burn.
Once boiling, turn heat to low and whisk in cheddar cheese, Romano cheese, gruyere cheese, salt and Worcestershire. Continue whisking until cheese is melted thoroughly.
Carefully pour mixture into large blender and blend on high until smooth.
Pour cheese sauce over noodles and stir.
Pour macaroni and cheese into 9-by-13-inch pan and spread evenly.
Heat oven to broil.
To make topping: In medium bowl, melt butter and stir in panko breadcrumbs.
Sprinkle breadcrumbs over macaroni and cheese; broil until golden brown.
