Combine the spinach, Monterey Jack cheese, egg, and onion.

Roll out pizza dough on a 14in x 10in greased baking sheet.

Spread spinach mixture within 1/2in. of edges.

Roll up lengthwise, seal ends, and place seam side down.

Brush with butter; sprinkle with Parmesan cheese.

Bake at 400°F for 25-27 minutes or until golden brown.