Roast beef Hawaiian roll sliders, or more affectionately called Sandy's Sandwiches, combine butter, garlic powder, Worcestershire sauce, and poppy seeds for a butter glaze that compliments these baked roast beef and cheese sandwiches.
Place the butter in a small pan over medium-low heat. Add the Worcestershire sauce, garlic powder, and sesame seeds. Stir with a small whisk until butter is completely melted.
Place the bottom of the buns in a casserole dish or 13X9 pan. Use a silicone brush to spread the buttery sauce over the bottom of the buns.
Layer the roast beef and then the cheese over the bottom of the buns. Spread more buttery sauce over the inside of the top of the buns. Place on top of the cheese.
Spread any leftover buttery sauce over the top of the buns. Sprinkle with the onion salt.