Combine sour cream, lemon juice, Worcestershire sauce, celery salt, paprika, mashed garlic, salt, and pepper in a bowl.

Add chicken breasts to the mixture, ensuring they are well coated.

Cover the bowl and refrigerate overnight to marinate.

Remove the chicken breasts from the marinade.

Roll each chicken breast in a mixture of Ritz and soda cracker crumbs.

Arrange the crumb-coated chicken breasts in a shallow baking pan.

Melt margarine in a small saucepan or microwave.

Spoon half of the melted margarine evenly over the chicken breasts.

Bake in a preheated oven at 300°F (150°C) for 1 hour.

Remove the pan from the oven.

Spoon the remaining melted margarine over the chicken breasts.

Return the pan to the oven and bake for an additional 45 minutes, or until the chicken is cooked through and the crumbs are golden brown.

Serve hot.