Bring butter and eggs to room temperature. Grease and lightly flour a loaf pan. Stir together flour, baking powder, salt, and nutmeg. In a large mixer bowl beat the butter or margarine at medium speed for about 30 seconds. Gradually add sugar, beating 6 minutes or until fluffy. Add vanilla. Add the eggs, one at a time, beating 1 minute after each and scraping bowl frequently. Gradually add dry ingredients to butter mixture, beating at low speed just until thoroughly combined. Turn batter into pan. Bake at 325 for 55 to 65 minutes or until cake tests done. Cool 15 minutes in pan. Remove from pan and cool on wire rack.