Preheat your oven to 425 degrees F. Spray 6, 6-ounce ramekin dishes with nonstick spray. Dust with cocoa powder. Set aside.
In a double broiler, or in the microwave, heat the butter and the chocolate until smooth. Remove from heat.
In a medium size mixing bowl, beat the sugar and eggs until the sugar dissolves.
Slowly add the chocolate mixture into the egg mixture. Start with just a bit of the chocolate mixture to temper the egg mixture. We don’t want to scramble our eggs!
Once all of the chocolate is combined with the egg mixture, add the salt and vanilla.
Fold in the flour.
Evenly divide the batter into the ramekins. Should be about 2/3 to 3/4 full.
Bake for 10 to 12 minutes, or until a toothpick insert in the side of one of the cake comes out with a few moist crumbs. The center should still be uncooked.
Let the cakes rest for about 5 minutes before carefully turning them over onto a plate. Make sure to use a hot pad. The ramekins will still be warm.