Having resolved countless marital disputes with nine simple words, we move now to the recipe. You will assemble these ingredients:
Put the flour, baking powder and baking soda into a bowl and mix it up. Add the butter, and cut it into the flour with a pastry blender. Everybody has one, right? Use two knives if you don't.
Add the buttermilk:
Mix that with a wooden spoon until it looks like its ready. Refrigerate it, preferably overnight, but for at least 30 minutes. Yeah, forgot to take a picture of that stage.
No matter how long you refrigerated the batter, get a tablespoon of butter and your third egg. Melt the butter, and beat that third egg like it is that asshole who constantly ragged on you in high school. Beat the motherfucker to death. Make it wish it had never been born. OK, it's an egg. It hasn't been born. But you get the picture. Then mix the cooled but still liquid butter into the beaten egg. Keep that shit ready.
Meanwhile, get the batter (or is it dough? fuck if I know) out of the refrigerator and put it on a floured cutting board. Flour your hands and spread it out into a circle of dough (or batter) about a half-inch thick. Use a circular cookie cutter (2-3/4 inch) and cut out the biscuits. You should get 20, although you probably will have to roll the dough (batter?) out a couple times.
Put some parchment paper on a cookie sheet.
Put your biscuits on the cookie sheet.
Brush your biscuits with the egg-butter mixture.
Bake your biscuits at 400 degrees (Fahrenheit, not Celsius -- if you're in a Celsius country, do the conversion. I can't because I was told there would be no math involved.) for 15-20 minutes, until golden brown. Eat them now, dammit. So good.