In a mixing bowl, combine softened cream cheese, mayonnaise, garlic powder, salt, and black pepper. Mix slowly at first, then stir well until smooth and creamy with no lumps remaining.

Add finely chopped spinach and shredded cheese into the bowl. Mix thoroughly until the ingredients are evenly combined and the filling looks thick and creamy.

Place tortillas on a flat surface. If needed, allow them to soften slightly at room temperature so they roll easily without cracking.

Spread an even layer of the spinach mixture across each tortilla, leaving a small space around the edges. Make sure the filling is evenly distributed.

Roll each tortilla tightly into a log shape, applying gentle pressure to keep it firm without pushing the filling out. Place seam-side down.

Wrap each roll tightly in plastic wrap and refrigerate for at least 1 hour to allow the filling to set and hold shape.

Remove from the fridge, unwrap, and place on a cutting board. Slice into small, even pinwheels using a sharp knife. Clean the knife between cuts for neat slices.

Arrange on a serving plate and serve chilled or slightly cool.