Directions:

Lightly butter the insides of six 6-ounce custard cups, sprinkle with sugar to coat, and tap out the excess. You can also use non-stick food grade silicone cups (the kind that are temperature-resistant from -40 F to 500 F), such as those made by Silpat.

In a medium stainless steel bowl placed in a skillet of hot, not simmering, water, melt the chocolate and butter, stirring often, until smooth. Remove from the heat. Measure 6 tablespoons into a small shallow bowl (a cereal bowl is perfect). Add the milk and stir well. Place in the freezer while preparing the rest of the recipe. Stir the cocoa and egg yolks into the remaining chocolate-butter mixture.

In a grease-free medium bowl, whip the egg whites with the cream of tartar until soft peaks form. Gradually beat in the sugar until the peaks are stiff and glossy but not dry. Fold about one-quarter of the egg whites into the cocoa mixture, then fold in the remaining whites. Spoon the batter into the cups, filling them half full. Set the remaining batter aside.

Remove the chocolate-butter mixture from the freezer; it should be firm. Using a dessert spoon, scrape up the mixture and roll into 6 truffle-like balls (they do not have to be perfectly round). Embed a truffle into the center of each custard cup, top with equal amounts of the remaining batter, and level the tops. Place the cups on a baking sheet. Cover the cups with plastic wrap and refrigerate for at least 3 hours. (The cakes can be prepared to this point up to 3 days ahead, covered, and refrigerated.)

Position a rack in the lower third of the oven and preheat to 400°F.

Bake until the cakes are puffed and cracked and a toothpick inserted in the center comes out gooey, indicating that the truffle is melted, about 12 minutes. Let the cakes cool for 3 minutes.

Run a thin knife around the inside of each cup to release the cake. Protecting your hands with a towel, invert a cup in the center of a dessert plate to un-mould the cake. Repeat with the remaining cakes. Serve immediately with a dollop of whipped cream.

Note: For more of a "restaurant-style" presentation, sift confectioners' sugar over the entire plate and garnish with drizzles or dots of raspberry or caramel sauce. Add whipped cream and a sprig of mint and fresh fruit when you plate your desserts, and it will look just marvellous to guests. See photo above for plating suggestion.

Difficulty level: Moderate.