Cook's Note: Goat's milk can be found at your local health food store or online.
Preheat the oven to 350 degrees F. Lightly grease four 6-ounce ramekins with nonstick cooking spray.
Set a small saucepan over high heat and add the granulated sugar to make caramel. Without stirring, let the sugar melt. As it melts, gently swirl the pan around to melt all the sugar evenly. When it turns dark amber, carefully divide evenly among the ramekins (take care as the caramel is extremely hot).
Combine the milk and superfine sugar in a saucepan and bring to a gentle simmer. Add the egg yolks, whole eggs and vanilla to a large mixing bowl. Whisk together until foamy, then add a little of the hot milk to temper the eggs. Stir to combine, then gradually add the rest of the milk (adding it all at once, or too much, will cook and scramble the eggs). Once completely incorporated, stir well and then divide evenly among the four ramekins. Line a turkey roaster with a kitchen towel and carefully place the ramekins on top. Place the roasting dish in the oven, then fill with hot water so it comes 3/4 of the way up the sides of the ramekins. Bake until the custards are set, 35 minutes. Remove the ramekins from the oven and allow to cool. Chill in the fridge before inverting onto a plate to serve.