Lightly coat a 9x13-inch glass baking dish with nonstick cooking spray.
In a medium bowl, combine 2 tablespoons ranch mix and chicken, stirring to coat. In a large skillet, heat oil over medium-high heat until hot. Add chicken and cook, stirring frequently, until no longer pink, about 5 to 8 minutes. Remove from heat and set aside until needed.
Slice Hawaiian rolls across the middle so you have tops and bottoms. It's easiest to keep them attached at this point. Place the bottoms in the prepared baking dish, then top with an even layer of sliced cheese.
Using a slotted spoon, transfer chicken evenly over cheese. Top chicken with crumbled bacon, then layer spinach evenly over chicken.
In medium bowl, beat eggs, Parmesan cheese and pepper. Pour evenly over the filling mixture.
Place the tops of the rolls over the filling. Melt butter and whisk together with pressed garlic and remaining tablespoon of ranch mix. Pour mixture evenly over the tops of the sliders, allowing the extra to soak into the bottoms. (It will make them crispy.)
Bake for 15-20 minutes, or until cheese is melted and rolls are toasted and golden. Let stand 10 minutes then cut apart and serve warm.