Place steaks between wax paper.
With a rolling pin, roll steaks as flat as possible.
Combine spinach, garlic, onion, and lemon juice in a saucepan with a small amount of water.
Cook until spinach is limp.
Drain and cool.
Wring spinach with your hands to remove any excess water.
Chop in a food processor or with a knife until fine.
Divide evenly among the 4 beef slices; roll up.
Place in a lightly greased pan.
Combine the soup and 1/2 c. (125 ml) water in a bowl; stir to blend.
Pour over steaks.
Bake at 350°F (175°C) for 30 to 40 minutes.