Bring first 5 ingredients and water to cover to a boil in a large saucepan; cook 15 to 20 minutes or until tender.
Drain, discarding bay leaf, and return potatoes and garlic to saucepan.
Add yogurt and next 3 ingredients; beat at medium speed with an electric mixer until smooth.
Stir in poppy seeds, lemon rind, and salt. Garnish, if desired.
*Plain nonfat yogurt and extra lemon rind may be substituted.