Astuce: Put the coconut oil in the refrigerator and keep it there even after you’ve measured it, so it is solid and incorporates well into the flour when you mix them together. And do add that touch of sugar to the berries and let them sit. The sugar encourages the berries to give up their juices, which are then absorbed by the shortcake. Miam!
Combine the berries with 1 tablespoon of sugar and toss. Set them aside at room temperature, covered.
Sift together the flour, salt and baking powder onto a piece of parchment paper. Transfer it to the bowl of a food processor fit with the knife blade. Add all but 1 tablespoon of sugar, pulse once or twice, then add the coconut oil and pulse until the mixture is about the size of coarse cornmeal, five or six times.
Whisk together the soy cream and the almond milk in a small bowl.
Transfer the mixture to a large bowl and fold in the soy cream mixture until the dough holds together. It will not be wet, but will hold together.
Press the dough into a 9-inch (22.5cm) circle on a piece of aluminum foil. Cut the dough into 8 equal-sized pieces. Sprinkle the remaining tablespoon of sugar in an even layer on top of the dough.
Preheat the gas grill with the plancha to 425F (220C).
When the grill and the plancha are hot, transfer the dough on the aluminum foil to the plancha, cover the grill and bake the shortbread until it is puffed and golden, which will take 12 to 18 minutes. The baking time depends on the grill you are using; check the shortcakes after 12 minutes.
When the shortcake is baked, transfer it immediately to a wire rack to cool. After about 10 minutes, remove the aluminum foil and return the shortcake to the rack to cool complete. To serve, divide the shortcake among 8 plates. Top each with an equal amount of the berries. Garnish with the mint leaves if desired, and serve.