Spacers will help you roll out the paste evenly.

You can use: 
  • Lollipop sticks (1.5 mm)
  • Candy floss sticks (4 mm)
  • Toffee apple sticks (5 mm)

 
If the piece you are rolling out is longer than the sticks, move them up and down. Keep the rolling pin on the sticks all the time, otherwise you will make indentations (the paste won't be level).