Preheat the oven to 350°F.

In a skillet over medium heat, cook the breakfast sausage until browned and fully cooked, breaking it apart as it cooks. Remove from heat and set aside.

In a bowl, whisk together the eggs, milk, salt, and pepper.

Pour the egg mixture into the same skillet and cook over medium heat, stirring gently until the eggs are just set but still soft. Remove from heat.

On a baking sheet, place the bottom halves of the mini bagels. Layer each with a portion of the cooked sausage, followed by a scoop of scrambled eggs, and top with a slice of cheddar cheese. Place the top halves of the bagels on each slider.

Melt the butter in a small bowl and brush it over the top of each bagel slider.

Bake in the preheated oven for about 10-12 minutes, or until the cheese is melted and the bagels are slightly toasted.

Remove from the oven and let cool for a couple of minutes. Garnish with chopped chives if desired. Serve warm.