In a large 10 to 12-inch oven-safe skillet, cook bacon to crisp. Remove from pan and drain. Chop into large pieces. Reserve drippings
In a large pot, salt the water and boil the pasta to al dente
Remove all but about 1 tablespoon of the bacon drippings. Heat pan to medium, add shallot and kale. Saute 1 to 2 minutes until kale is wilted. Remove to a platter with a slotted spoon.
Add 2 to 3 tablespoon more of the bacon drippings to the pan. Add flour, nutmeg, and pepper. Cook 1 to 2 minutes until lightly browned. Add milk and whisk until smooth. Cook until the mixture begins to thicken. Add cheese and stir until cheese melts.
Add pasta, kale, shallots, and bacon to the cheese sauce. Gently stir to combine.
In a small bowl, add butter or oil to crushed crackers and mix to combine.
Top pasta mixture with crushed crackers.
Bake at 350°F until the mixture is hot throughout and crumbs begin to brown.
Remove from oven, allow to cool 5 minutes. Serve hot.