Prep: 1. Separate the eggs, and place in separate bowls. Allow the eggs and butter to come to room temperature. 2. Preheat the oven to 350. Butter a 9 x 5 inch loaf pan and set aside. Make: 1. Whisk together the flour, baking powder, salt, nutmeg. 2. In a separate bowl, use an electric mixer to beat butter. Add half the sugar, and beat the mixture on medium-high speed until well-blended. Add the rest of the sugar, and continue to beat until light and fluffy, scraping down the sides of the bowl as necessary. Add the egg yolks, one at a time, and beat until incorporated. 3. Mix in the dry ingredients by hand with a spatula. Add the vanilla and stir until incorporated. 4. In a clean, dry bowl, use an electric mixer to beat egg whites until foamy, add cream of tartar (if using) and beat on high until soft peaks form. Fold them gently into the batter until totally combined. 5. Pour batter into the greased loaf pan. Bake at 350 degrees for 1 hour and 10-15 minutes, or until toothpick inserted comes out clean and loaf is golden brown. 6. Allow loaf to cool in the pan on a cooling rack for 5 minutes; then invert and allow cake to cool to room temperature.
If you don't have cream of tartar on hand it's not strictly necessary, but it does really help the egg whites to get to the desired consistency. You can often find it in the bulk spice section, which is great since you'll need it for very little else. Room temperature egg whites, and a very clean, very dry bowl is also key to get the egg whites to the proper consistency. We love this with the Berry Sauce in the Gatheredtable Recipe Library, it's also great as the cake in the Grilled Strawberry Shortcake Kebabs and the Grilled Pound Cake with Basil Plum Compote.