►Melt butter in a small skillet set over medium heat. Add breadcrumbs and toast until golden brown, about 4 to 5 minutes. Sprinkle in fresh sage and stir to combine. Set aside.
►Cook bacon in a large skillet set over medium heat until browned and crisp. Drain on a paper towel–lined plate and cool. Roughly chop bacon and set aside.
►Melt butter in a large saucepan set over medium heat. Add shallots and garlic, stirring frequently to avoid burning. Cook until shallots are translucent, about 3 to 4 minutes.
►Sprinkle flour into saucepan. Stir constantly with a wooden spoon until flour has been fully incorporated, about 1 minute.
►Slowly whisk in milk and heavy cream. Bring liquid to a simmer, then reduce heat to medium-low.
►Whisk in muenster and parmesan cheeses until melted. Add salt, black pepper, cumin, and thyme. Whisk to combine.
►Pour cheese sauce over cooked pasta and stir to combine. Add reserved chopped bacon and stir to combine.
►Transfer mac and cheese to a 9-inch-by-13-inch casserole dish. Sprinkle cooled breadcrumbs evenly over the top.
►Bake for 25 minutes, or until cheese sauce is bubbly around the edges of the baking dish.