Place chocolate and butter in a large heatproof bowl. Either over a saucepan of simmering water or in the microwave in 15-30 second bursts, stirring frequently, melt the two together. Off the heat, whisk in sugar, which should cool the mixture down significantly. Whisk in salt, then eggs, one at a time. Stir in flour.

Cover bowl with plastic wrap and let sit at room temperature for 30 minutes. The batter will thicken a bit as it stands.

Heat over to 325 degrees F

Either coat a 12-cup muffin tin with nonstick spray or line with cupcake papers. Spoon batter halfway into each cup and bake for 25 to 30 minutes, or until a toothpick inserted into the center of cakelets comes out batter-free. (Fudgy crumbs are to be expected)

Let cool on a rack for 5 to 10 minutes before un-molding. Puffed tops will fall a little as they cool.