1Preheat oven to 200°C.
2Sprinkle flour on work surface. Unfold pastry sheet on work surface. Roll out to 12 x 10 rectangle.
3Squeeze excess water from spinach.
4Spread spinach evenly over pastry then sprinkle with Beemster.
5Starting at a long side, roll up like a jelly roll.
6Cut into about 20 (2cm) slices.
7Place the slices, cut-sides down, onto 2 baking sheets lined with parchment paper.
8Beat egg with garlic powder and 1 tablespoon water. Brush onto pinwheels.
9Bake 15 minutes or until golden brown.
10Remove from baking sheets and cool slightly. Serve warm or at room temperature.