Heat oven to 350 degrees. Grease bottom only of 9x5 inch loaf pan. Beat eggs in large bowl. Add sugar, eggnog, margarine, rum extract, and vanilla; blend well. Lightly spoon flour into measuring cup; level off. Add flour, baking powder, salt and nutmeg; stirring just until dry ingredients are moistened. Pour into greased pan. Bake for 45 to 50 minutes. Cool in pan for 10 minutes then remove. Cool completely.
Note: Dairy eggnog freezes well so freeze some extra during the Christmas season and have a treat during the summer! You can freeze eggnog in 1 cup containers so that you can make this in July and think of Christmas. You can double this but not any larger. For a change, pick your favorite chocolate quick bread recipe and marble together.