Preheat oven to 350 degrees F. Grab a 9-inch x 13-inch pan and an 8-inch x 8-inch pan, large baking sheet, OR an oversized baking dish for these sliders.
Cook bacon on the stovetop or in the oven. (If using the oven to cook bacon, preheat to 400 degrees F instead and then reduce heat to 350 when bacon is done.) Transfer to a paper towel-lined plate to drain.
Slice rolls in half to create a set of tops and bottoms. Place bottom halves into pans and spread with mayo.
Layer bottom buns with turkey, ham, bacon (breaking it into pieces to fit as needed), and then half slices of cheese. Each layer should cover the previous layer edge to edge. Place top buns over the filling.
In a medium bowl, melt butter. Mix in mustard, onion powder, Worcestershire sauce, sugar, and poppy seeds. Brush butter mixture over the rolls or pour it evenly all over the top.
At this point, you can get baking OR cover sandwiches with plastic wrap and store them in the fridge until ready to serve.
Bake sliders for 15-18 minutes until cheese is melted and rolls are golden on top.
Remove from oven and let cool for 5 minutes before cutting into individual sliders. Serve warm.