Preheat the oven to 325 degrees F. Spray a 2 (24-count) mini muffin tins with nonstick cooking spray.
In a double boiler melt the chocolate with the butter and espresso powder until smooth.
In a large bowl whisk together the flour, 1/2 teaspoon of salt, and the spices. In another small bowl whisk together the eggs, egg yolks and vanilla. Set both aside.
Remove the pot of chocolate from the double boiler. Stir in the sugars until completely incorporated. At this point the chocolate should be warm but not hot. Add the egg mixture and stir until combined. Fold in the flour mixture in 2 stages, being careful not to over mix. Using a small ice cream scoop divide the batter into the mini muffin tins. Tap gently to level batter. Sprinkle each with a bit of sea salt.
Bake for about 15 minutes until mostly set. A tester will not come out completely clean. Remove the pan from the oven and transfer the brownies to a serving platter when cool enough to handle.