"Quatre Quarts" Pound Cake

Here is a cake recipe that's really piece of cake: the pound cake. The name of this cake comes from the fact that all ingredients are weighed and used in equal proportions (traditionally, one pound each of flour, butter, eggs and sugar). In French we call it "Quatre quarts" (litterally "4 fourths"), also reflecting the fact that all 4 ingredients are used in equal amounts.
It is a very simple yet deliciously fragrant and addictive cake. No additional flavoring is needed if you choose good quality products. The biggest challenge is to beat and blend the ingredients well enough to make the cake moist and fluffy (otherwise "pound cake" will have a very different meaning!). So:

• Take 3 large eggs and weigh them. They should weigh about 2 oz. each (60 grams).
• Weigh the same amount of all-purpose flour: 6 oz. (180 grams) or 1 1/4 cups
  
• Weigh the same amount of sugar: 6 oz. (180 grams) or 3/4 cup
• Weigh the same amount of butter: 6 oz. (180 grams) or 3/4 cup (1 1/2 sticks).
  You can use unsalted and salted butter (50-50), or unsalted butter alone with a good amount of salt (up to 1 teaspoon). The first time I've used salted butter in a pound cake, I thought I'd just made a huge mistake (I intended to use unsalted butter) and panicked. But it turned out to be really good, maybe even better than with unsalted butter: all the simple and earthy flavors of the butter, sugar and egg are enhanced by the salt. And it gives the cake the unique flavor of Britany pastries, that also use "beurre demi-sel". Free trip to the beach!

1. Pour the sugar in a large bowl. Pour the melted butter* and blend it in with a wooden spoon until smooth.
2. Separate the egg yolks from the whites. Set the whites aside.
3. Add the egg yolks to the sugar-butter mix. Stir well (with the wooden spoon). The more energetically you beat, the fluffier the cake.
   
4. Slowly add the sifted flour and incorporate it gradually as it falls on the batter.
5. Add some salt (up to a whole teaspoon). This isn't needed if you are using salted butter.
6. Add a pinch of salt to the egg whites and beat until stiff. If the egg whites have been beaten enough you should be able to flip the bowl upside down and they won't fall down... Up to you to take the risk!
   
7. Incorporate the egg whites to the batter, one big spoonful at a time, very delicately, making under-and-over motions until evenly blended. The foam (air bubble) shouldn't "break". This is also a very important step in getting a fluffy cake.
   
8. Pour the batter in a buttered round metallic cake mold (about 12" 9-10 inches in diameter).
9. Bake at 350F (180C) for about 45 minutes or until baked (if you stick a knife in the center of the cake it should come out dry).

* For long I've melted butter directly in the cake pan, in the preheating oven. This way the mold was buttered and I didn't have to wash another dish. But it's easy to "over melt" the butter (i.e. get to the point where it's bright yellow and oily rather than white and foamy). Now that I have a micro-wave (it's only been a few months, believe it or not) I find it even more convenient to melt the butter in there. My micro-wave even has a "melt butter" button!