Make the flourless cake. Preheat oven to 350°F. Line cupcake tin with 12 liners. Set aside.

In a double boiler, add chocolate and butter. Place over a saucepan filled with water so that water is not touching bottom of double boiler. Cook over medium-high heat, stirring until chocolate and butter have almost melted. Remove from heat and whisk in the kosher salt until smooth. Set aside.

Meanwhile, separate egg whites and yolks into two bowls, placing the whites in a mixing bowl. Using a stand or hand mixer, whip egg whites on high until soft peaks. Then slowly add sugar a little bit at a time, whipping until almost stiff, glossy peaks form. Set aside.

Whisk the egg yolks into the cooled chocolate mixture until evenly combined (cooled to the point that it won’t cook the yolks). Using a spatula, fold egg whites into the chocolate mixture in 4 increments until just combined. Divide batter evenly into the cupcake liners. Bake for about 20 minutes. Tops will spring back when ready. Remove from the oven. Slight collapsing is normal.

While the cupcakes bake, make the blackberry sauce. Into a small saucepan, add all the blackberry ingredients. Cook on medium heat until sugar is dissolved, about 5 minutes. Pour mixture into a high powered blender, blending until smooth. Pour sauce back into the saucepan through a fine mesh sieve to catch the seeds. Cook for another 5 minutes until sauce begins to reduce and thicken. Remove from heat and allow to cool completely. Store leftovers covered in the fridge.

Make the frosting. (If you don’t have my book, here’s a similar frosting recipe.)

To assemble, add a dollop of frosting to each cupcake, and pull a spoon in a circular motion through the center to create a divot. Spoon a bit of blackberry sauce over the middle. Top with an additional blackberry and a sugared sage leaf, if desired. Best served same day.