Thaw one roll of fillo dough, following thawing instructions on package.
Preheat oven to 350ºF.
Unroll and cover the fillo pastry sheets with a damp towel or plastic wrap to prevent drying out.
Lightly coat muffin pan or cup with cooking spray.
Place one sheet of fillo on a cutting board and lightly coat with cooking spray. Layer and repeat with 4 more sheets. (Recipe or personal preference may substitute brushing with melted butter, olive oil or egg wash.) If shell is for dessert item, lightly sprinkle each layer with sugar after spraying. Finely chopped or ground nuts between sprayed and sugared fillo layers add wonderful flavor.
A general guide is to cut the fillo about 1″ larger than the diameter of the cup or muffin pan cavity, so that the fillo circle is large enough to go completely up the sides of the cavity. To make fillo cups for 2 1/2″ – 3″ muffin pan/cup, cut 4″ circles; for 4″ muffin pan/cup, cut 5″ circles; and for 5″ muffin pan/cup, cut 6″ circles.
Place layered circles into the sprayed pan. Carefully push fillo into the cavity, pressing firmly against bottom and sides.
TO MAKE SQUARES:
Use the same method as with cups. Use 5 sheets per stack to cut the squares into the desired size. When you push them into the pan, leave the points sticking up.
Other shapes: Ovenproof bowls can be used to bake fillo for various sized cups. For example, if you need a 5″ diameter cup, spray and stack 5 sheets of fillo. Cut circle 6″ in diameter and press into a 5″ bowl.
Reroll unused fillo sheets and follow storing instructions on package.
Bake empty shells about 8-10 minutes or until fillo is golden brown. Cool 5 minutes. Remove and fill.