In a large pot, combine chicken, garlic and 3 quarts (12 cups) water.

Bring to a simmer over medium-high heat; lower heat and cook at a gentle simmer, skimming off and discarding any foam from the surface until chicken is just cooked through, about 45 minutes.

Remove chicken from liquid and use two forks to remove meat from bones.

Set meat aside and return bones to pot with broth.

Continue to cook until broth is flavorful, an additional 45 minutes.

Strain liquid into a large bowl and skim fat from surface.

Alternately, cool, cover and refrigerate until fat has solidified on surface of broth, at least 6 hours and up to 2 days.

Beat egg whites in a large bowl until they hold soft peaks, about 2 minutes.

Stir egg yolks, matzoh meal, oil or chicken fat, 1/2 teaspoon of the salt and 1/2 cup cold water together in a medium bowl.

Fold egg whites into matzoh mixture until combined (don't worry if there are lumps).

Cover and refrigerate 30 minutes.

Return broth to a saucepan and bring to a simmer.

Add chicken, carrots and remaining 1/2 teaspoon salt.

Moisten your hands and gently form matzoh mixture into balls a little larger than walnuts.

Carefully add balls to simmering broth.

Adjust heat, cover the pan and cook at a gentle simmer until balls are light and fluffy and cooked all the way through, about 20 minutes.

Stir in spinach just before serving.