Cook pasta al dente according to package instructions. Drain, rinse with cool water, and reserve.

In a non-stick skillet, saute bacon, shallot, and jalapeno until bacon is crispy brown. Remove mixture from pan and drain on paper towel.

Add panko crumbs to pan and toast over medium heat until lightly browned. Remove from heat. Combine bacon mixture with crumbs and reserve.

In a heavy bottom sauce pan, melt butter over med-low heat, add in sage leaves; cook, stirring constantly, until butter is golden brown. Remove from heat. Remove sage leaves only and add them to the topping mixture.

Return brown butter to heat and add flour. With a wire whisk stir mixture constantly until bubbly, about 2-3 minutes. Slowly pour in milk, stirring continuously until butter flour and milk are well combined. Allow sauce to come to a gentle boil, stirring occasionally.

Reduce heat to low and gradually add shredded cheese, stirring after each addition until cheese is melted and incorporated into sauce. Remove from heat.

Stir in cayenne and black pepper. Adjust according to taste. The sauce should not need salt, but add if necessary.

Preheat oven to 350 degrees.

In a large bowl, combine cooked pasta with a generous amount of sauce. Should be well coated and very cheesy. Pour mixture into buttered casserole or cast iron skillet. Sprinkle with topping mixture.

Bake for 30 minutes until top is lightly browned and cheese is bubbly around edges.