Preheat your oven to 350°F (175°C). Gather your ingredients and grease a baking dish.

In a medium saucepan over medium heat, melt ¼ cup of butter. Whisk in ¼ cup of flour and cook for about 1 minute.

Gradually add 2 cups of milk while stirring continuously until the mixture thickens over 3-4 minutes.

Stir in 2 tablespoons of Dijon mustard, 1 teaspoon of garlic powder, salt, and pepper. Fold in ½ cup of grated Parmesan cheese.

Slice the Hawaiian rolls in half horizontally, keeping them connected. Place the bottom half in the greased baking dish.

Layer turkey slices evenly over the bottom half. Add bacon if desired and pour the cheese sauce over everything.

Place the top half of the rolls over the filling. Brush melted butter over the tops.

Cover with foil and bake for 15 minutes. Remove foil and bake for another 5-7 minutes until golden brown.

Let cool for about 5 minutes, then cut into individual sliders and serve warm.