Preheat oven to 350°F; grease a 9x13-inch dish. Cook bacon in a large skillet until very crispy; drain on paper towels and crumble.
Cook macaroni according to package until al dente; drain and set aside.
Melt butter with 2 tablespoons reserved bacon fat in a large pot over medium; whisk in flour and cook 2 minutes.
Slowly whisk in milk and cream constantly about 6-7 minutes until thickened.
Remove from heat; stir in cheddar, gouda, mustard, salt, and pepper until completely melted and smooth.
Fold in macaroni and three-quarters of bacon to distribute evenly.
Spread evenly in dish.
Mix panko with remaining bacon; sprinkle over top.
Bake 25-30 minutes until bubbly and golden brown on top; garnish with parsley before serving.