Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper and lay the thick-cut bacon strips in a single layer. Bake for 15-20 minutes, or until crispy and golden, then crumble into bite-sized pieces.

In a mixing bowl, whisk together large eggs, milk, salt, and pepper until well combined. Melt butter in a skillet over medium heat; pour in the egg mixture. Cook gently, stirring occasionally until the eggs are set, about 5-7 minutes. Mix in shredded cheeses until melted and creamy.

Lower oven temperature to 350°F (175°C). Slice the Hawaiian rolls horizontally, maintaining them connected. Layer half of the egg mixture over the rolls, add crumbled bacon, top with remaining egg mixture, and place the top half of the rolls back on.

In a small bowl, whisk together melted butter, Dijon mustard, and garlic powder. Brush this mixture generously over the tops of the assembled sliders.

Cover the baking dish with aluminum foil and bake for 15 minutes. Remove the foil and bake for an additional 5-10 minutes, until tops are golden.

Remove sliders from the oven, let cool for a few minutes, then slice into individual servings. Serve warm, optionally with avocado or hot sauce.