Place the chopped dark chocolate and heavy cream in a small saucepan. Heat gently over low heat, stirring constantly, until the mixture is fully smooth and glossy. Avoid boiling.

Transfer the ganache to a bowl and chill for 20–30 minutes until it’s thick but still scoopable.

Spoon the chilled ganache into 1-tablespoon mounds on parchment. Freeze for at least 20 minutes until solid.

In a large bowl, beat the softened butter with the brown and cane sugar for 2–3 minutes until pale and fluffy.

Beat in the milk and vanilla just until combined.

In a separate bowl, whisk together the flour, Dutch-processed cocoa, cornstarch, baking soda, baking powder, and salt.

Add the dry mix to the wet ingredients on low speed and mix just until combined; do not overmix.

Cover the dough and let it rest for 30 minutes at room temperature.

Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

Portion about 50 g of dough, flatten it, place one frozen ganache ball in the center, and wrap dough fully around the ganache.

Seal edges well and roll into a smooth ball. Arrange on the prepared sheet about 2 inches apart.

Bake for 10–12 minutes, until edges look set while centers remain soft.

Use a round cutter to press each warm cookie gently into a round shape and let cool for 5–10 minutes before serving.