Preheat oven to 325°F (160°C Gas Mark 3). Mix flour baking powder salt and nutmeg in medium bowl. Set aside. Beat butter and sugar in large bowl with electric mixer on medium speed 5 minutes or until light and fluffy. Beat in eggs 1 at a time. Gradually beat in 1/2 of flour mixture. Mix in vanilla and remaining flour. Pour batter into greased and floured 9 x 5 x 3-in (23 x 12 x 8 cm) loaf pan. Bake 60 to 65 minutes or until toothpick inserted in center comes out clean. Cool on wire rack.