In a large skillet over medium heat, warm the olive oil.

Add the onion slices and a pinch of salt. Lower the heat to medium-low and let the onions cook slowly, stirring occasionally, for about 25 minutes until caramelized.

Set the caramelized onions aside to cool slightly.

Preheat your oven to 350 degrees Fahrenheit.

In a medium bowl, whisk together the melted butter, poppy seeds, minced garlic, and Worcestershire sauce until well combined.

Split the mini Hawaiian rolls in half horizontally and place the bottom halves on a baking sheet.

Spread the mayonnaise over the bottom buns, layer with half the ham slices, then Swiss cheese, followed by the remaining ham, honey mustard, and then caramelized onions.

Close the sandwiches with the top halves of the rolls.

Brush the poppyseed mixture generously over the tops of the buns.

Bake in the preheated oven for about 10 to 15 minutes until the cheese is melted and the tops are golden. Tent with foil if they brown too quickly.

Enjoy these sliders hot out of the oven. They’re best when gooey and fresh!