• Step 1 – Prep Ingredients (5 minutes)
• Chop the dark chocolate into small pieces and set aside. If using chocolate callets, you can skip chopping.

Step 2 – Make Custard Filling (10 minutes)

• In a clean mixing bowl, whisk together 1 egg and 1 egg yolk.
• Add sugar, milk, heavy cream, and condensed milk. Mix until smooth.
• Strain the mixture through a fine sieve to remove lumps for a silky texture.

Step 3 – Assemble & Bake (20 minutes)

• Preheat oven to 200℃ (392℉) for 10 minutes, top and bottom heat.
• Place 10g chocolate chips in the bottom of each tart shell.
• Pour custard filling into tart shells until 80% full.
• Bake for 20 minutes. Check in the last 5 minutes—cover with foil if browning too quickly.

Step 4 – Decoration (5 minutes)

• Make the Chocolate Ganache: Place the reserved 50g of chopped chocolate in a small heatproof bowl. Melt it over a double boiler (or a bowl set over a pot of simmering water, ensuring the water doesn't touch the bowl and the temperature stays below 60°C / 140°F). Stir until smooth and lump-free. Let it cool slightly (so it doesn't melt the tart surface when drizzled).
• Once tarts are out of the oven, let them rest for 1 minute. Drizzle melted chocolate on top.
• Sift a thin layer of cocoa powder over the tarts to create the classic "dirty" look. You can also decorate with assorted chocolate pearls.
• For an extra touch, you can pipe the chocolate ganache in a grid pattern or random lines over the pearls.
• Serve warm for a molten center, or reheat 10 seconds in the microwave to bring back gooeyness.