Thaw the frozen chopped spinach completely, then squeeze out all excess water using a clean kitchen towel or paper towels to prevent soggy pinwheels.

In a medium bowl, combine softened cream cheese, well-drained spinach, Parmesan cheese, mayonnaise, sour cream, garlic powder, and onion powder; mix until smooth, then season with salt and pepper.

Lay a tortilla flat and spread 1/4 to 1/3 cup of the spinach dip mixture evenly over its surface, extending nearly to the edges.

Tightly roll each prepared tortilla from one end to the other to create a snug log, repeating with the remaining tortillas.

Optionally, wrap each rolled tortilla in plastic wrap and refrigerate for 15-30 minutes to firm up the cream cheese for easier slicing.

Preheat your oven to 375°F (190°C), unwrap the tortillas, and slice each roll into 1/2-inch thick pinwheels using a sharp knife.

Arrange the pinwheels cut-side up on a baking sheet and bake for 8-12 minutes, or until the edges are lightly golden and the filling is warm and bubbly.

Let the pinwheels cool for one or two minutes before serving them warm.