First, make the small cakes:

1. Prepare the pan. Generously butter 8 cups of a nonstick muffin pan (with a capacity of 70ml /⅓ cup each). Sift together the flour, baking powder and salt into a small bowl.
2. Make the batter. In a large mixing bowl, beat the sugar and softened butter at medium speed until creamy with a hand mixer, about 2 min. Reduce the speed to low, add the egg and beat for 1 min. Beat in half of the flour mixture. Scrape down the sides of the bowl with a spatula as needed. Add the milk and yogurt and beat for 1 min. Add the other half of the flour mixture and beat just until incorporated, still at low speed.
3. Refrigerate. Spoon the batter evenly into the prepared muffin cups. Do not fill them all the way to the top, ¾ full is best! Cover the pan with plastic wrap (it shouldn’t touch the batter) and refrigerate for at least 4h or overnight.
4. Bake the cupcakes. Set a rack in the middle of the oven and preheat the oven to 250°C (480°F). Put the muffin pan in the oven and reduce the temperature to 180°C (350°F). Bake for 20 min or until the tops are slightly golden and a toothpick inserted into a cauldron cake comes out clean. Let the cauldron cakes cool down in the pan for 5 min before transferring them to a cooling rack. Let them cool down completely before continuing.
5. Carve. Turn the cauldron cakes upside down so that the dome is at the bottom. If they can’t stand straight, slice off a bit of the bottom to flatten them. Using a paring knife, hollow out a 3cm (1 in) round piece, about 2cm (0.8 in) deep from the center of each cauldron cake, leaving each cauldron with a 0,5cm (0.2 in) rim.

Then, decorate the cauldron:

1. Prepare the feet of the cauldrons. With a long-bladed knife chop 5 chocolate squares into 32 even small pieces. These will be the ‘feet’ of your cauldron cakes. Finely chop the rest of the chocolate. Line a baking tray with baking parchment or aluminum foil. Check the circumference of the cauldron cakes’ bottoms and place the chocolate pieces/cauldrons’ feet accordingly in groups of 4 on the tray.
2. Melt the rest of the white chocolate. Fill a saucepan with 5 cm (2 in) of water and place over low heat. Place the rest of the chopped chocolate into a smaller saucepan. Place this pan on top of the first pan (its bottom shouldn’t touch the water). Melt the chocolate, stirring with a spatula from time to time. Once melted transfer the chocolate to a small bowl, a bit larger than the cauldron cakes’ circumferences.
3. Glue the feet to the cauldrons. Gently dip the bottom of each cauldron cake 2cm (0.8 in) deep into the melted chocolate and place them on their ‘feet’. The melted chocolate will work as glue and when it will have set the feet will be attached to the cauldron.
4.  Decorate the rims of the cauldrons. Pour the rest of the melted chocolate into a piping bag. Cut off the tip, less than 0,5cm (0.2 in), and pipe the melted chocolate on the cauldron cakes’ rims. Let the chocolate on the cauldron cakes harden and set at room temperature. If the chocolate doesn’t seem to set you can put the cauldron cakes in the fridge for 20 min. Then, cover the cauldron cakes with the gold glitter (I used a brush but you could certainly do it with your finger).

Lastly, make the felix felicis potion:

1. Make whipped cream. Pour the cream into the cold mixing bowl and beat with a hand mixer at slow speed for 2 min. Sprinkle the caster sugar and increase the speed to medium. Beat until medium peaks form, about 1 min. Add the dulce de leche (and optionally the cream of tartar) and increase the speed to high. Beat until stiff peaks form, about 30 seconds to 1 min.
2. Fill the cauldron cakes. Spoon the whipped cream into a piping bag, snip off the tip and fill the cauldron cakes. Sprinkle a bit of gold glitter on top of the filled cauldrons. Here you go, your cauldron cakes filled with felix felicis are ready!