My hubby took one bite, and immediately downed 2 more

Brush the melted butter over the top of the buns, then sprinkle with sesame seeds.
Cover the dish with aluminum foil and bake for 15 minutes. Remove the foil and bake for an additional 10 minutes, or until the tops of the buns are golden and the cheese is melted.
Let the casserole cool slightly before slicing into sliders and serving.
Variations & Tips
For a different flavor, you can add a packet of dry onion soup mix to the beef mixture or try using Swiss cheese instead of cheddar. If you have picky eaters, you could serve the beef mixture on the side and let them build their own sliders. For a bit of a kick, add some diced pickles or jalapenos into the beef mixture. Lastly, you can swap out the ground beef for ground turkey or chicken for a lighter version of this delicious dish.