Preheat the oven to 350°F.

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

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

Pour the egg mixture into the skillet and cook over medium-low heat, stirring gently until the eggs are scrambled and just set, about 5-7 minutes.

While the eggs are cooking, place the split bagels on a baking sheet and toast them in the oven for about 5 minutes until lightly golden.

To assemble the sliders, layer a slice of cheddar cheese on the bottom half of each toasted bagel.

Add a scoop of the scrambled eggs, followed by a portion of the cooked sausage.

Top with avocado slices and a few spinach leaves.

Place the top half of the bagel on each slider.

Serve immediately while warm.