Prepare a 6-inch square cake pan. Grease the sides of the pan with a little oil and set aside.
Break the chocolate into pieces and place in a heatproof bowl over a pan of simmering water. Make sure the bottom of the bowl doesn’t touch the water, or you will burn the chocolate. Stir until melted and mixed, then add the coconut oil, milk, and sugar. Stir to combine. Set aside and allow to cool.
Preheat the oven to 400°F.
Whisk the egg whites with a pinch of sea salt until soft peaks form.
Sift all the flours and starch into a large bowl, add cocoa powder and egg yolks, and mix to combine. Stir in the melted chocolate mixture, then gently fold in the egg whites until smooth.
Pour the chocolate mixture into the baking pan and arrange cherries on top. Bake for 20 minutes. Cool on a wire rack before serving.