The Blender Magic & The "Reserve": In your blender, combine the room-temperature eggs, sugar, oil, milk, and vanilla. Blend until perfectly smooth. Add your pure cocoa powder and blend again. Once you have a smooth, velvety chocolate liquid, take exactly 150 ml of this mixture out of the blender and set it aside in a cup.
Fold and Bake: Pour the remaining blender batter into a mixing bowl. Gradually fold in your flour and baking powder in three parts, mixing gently by hand just until the dry lumps disappear. (Check the "Baking Tips" section above to see exactly how to fold this traditional Moroccan Meskouta for maximum fluffiness). Pour the batter into a greased and floured baking dish, and bake in a preheated oven at 180°C (356°F) for 25–30 minutes. (Mama's Golden Rule: Do not open the oven door to check the cake until you can smell the rich baked chocolate aroma filling the kitchen, or your cake will sink!) Bake until a toothpick comes out clean.
Simmer the Chocolate Sauce: While the cake is baking, pour the 150 ml of reserved batter into a small saucepan with 150 ml of milk. Heat it gently on the stove, stirring continuously so it doesn't stick. As soon as it reaches a gentle boil, remove it from the heat and stir in your 55% dark chocolate pieces until perfectly melted. (Wondering why you shouldn't substitute this with milk chocolate? Read the "FAQ" section in the post above before making this sauce!) Let this sauce cool down, then pop it in the fridge to chill.
The Hot-and-Cold Soak: The moment your easy chocolate blender cake comes out of the oven, use a fork or skewer to poke small holes all over the hot surface. Immediately pour your chilled chocolate sauce evenly over the top. (The "Hot & Cold" Rule is the absolute secret to this recipe) Let it chill in the fridge for at least 3 hours to set. Slice into squares and serve this irresistible Moroccan chocolate delight alongside a steaming glass of fresh mint tea!