Bread & Barley Knock-Off Macaroni & Cheese with Pork Belly

Recently, upon trying the newest pub in our town, Bread and Barley, Dan and I had the most tremendous macaroni and cheese.  They make it with smoked gouda, miso cheese, and pork belly.  I made a homemade version today:

8 oz elbow macaroni, cooked el dente and drained
8 oz chopped pancetta
1 stick butter
1/4 c flour
2 C 2% milk
8 oz shredded Asiago Fresco
4 oz shredded Parmesan
4 oz shredded 4-cheese blend (Cheddar, Monterey Jack, Asadero, Queso quesadilla)
1 tsp dry mustard
salt/pepper to taste
1 C. panko bread crumbs

Cook the elbows el dente and set aside.  Meanwhile, sauté the pancetta in 3 T butter until just crisping.
In a pot, melt the remaining butter and add the 1/4 c flour to make a roux.  When it is golden brown, add the milk and cook until warm.  Add the cheeses and whisk until melted.  Whisk in dry mustard and salt & pepper.  Add the elbow macaroni to the cheese sauce and mix.  Pour the pasta/cheese mix into a casserole dish or cast iron roasting pot.  In the butter/pancetta pan, add 1 C. panko bread drums and stir until butter is absorbed.  Top the casserole with the bread crumb mixture.  Bake for 25 minutes at 375 degrees until top is golden brown.  Serve.