You can use two 8 or 9-in (20 or 23 cm) cake pans. Butter and flour the pans or spray them with baking spray. To make it even easier to remove the cakes, consider lining the pans with parchment paper. Measure 4 tablespoons (26 g) of powdered milk into a bowl and pour in 1⁄2 cup (120 ml) of water. Whisk or stir until the powdered milk is completely dissolved. If you'd like, use 1⁄2 cup (120 ml) of liquid milk instead of reconstituting the powdered milk. Put 4 cups (520 g) of all-purpose flour into a large bowl and add 1 tablespoon (14 g) of baking powder. If you'd like the cake to be lightly spiced, add 1/2 teaspoon (1 g) of grated nutmeg. Whisk the dry ingredients for about 30 seconds so that they are fully combined. Place 1 cup (226 g) of softened unsalted butter, 1 cup (226 g) of margarine, and 2 cups (400 g) of sugar into a large mixing bowl. Use an electric or stand mixer to beat them together on medium speed.  The creamed mixture should become pale and fluffy. If you don't have a mixer, use a wooden spoon. Keep in mind that it will take 5 to 10 minutes longer to cream the mixture by hand. Keep the mixer running while you add 1 egg at a time to the creamed mixture. Once the egg is incorporated, add the next egg. Continue beating them in until you've added a total of 10 eggs. Room temperature eggs will blend into the batter the best. If they're cold the batter may separate, but it will come together again when you add the dry ingredients. Turn the mixer up and beat the batter so that it becomes pale. Then add 1 tablespoon (15 ml) of vanilla and beat it until it's incorporated. Turn the mixer to low and beat in about 1/3 of the dry mix. Then beat in half of the milk before you add another 1/3 of the dry mix. Beat in the rest of the milk and then the rest of the flour. Stop beating as soon as the last of the dry mix is incorporated.  It's fine if there are a few lumps in the cake batter. Over beating the batter will make the cake tough and dense.

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Write a summary of the previous text in Chinese:
烤箱预热至180℃，同时将2个圆形烤盘里抹上油脂。 将奶粉用水溶化。 在碗里倒入面粉、泡打粉以及肉豆蔻粉，搅拌均匀。 花5到10分钟的时间将黄油、人造黄油以及白糖打发至顺滑。 将10个鸡蛋一个接一个地磕到碗里，同时不断地搅拌。 用中高速将鸡蛋和黄油白糖的混合物搅打2分钟，然后加入香草精。 交替加入干的混合料以及牛奶。