Place the whole peppercorns on a cutting board and press the flat side of a heavy knife down firmly to crack them into coarse, uneven pieces. You want irregular shards, not a fine powder.

Pull a double shot of espresso (60 ml) directly into your mug. The shot should be dark brown with a thin tan crema on top.

Add the finely chopped dark chocolate and granulated sugar to the hot espresso immediately. Whisk with a small whisk for about 30 seconds until the chocolate is fully melted and the mixture is glossy with no visible lumps.

Stir the cracked black pepper into the chocolate-espresso base. Let it sit for 1 minute so the pepper infuses into the liquid before you add the milk.

Pour 220 ml of cold whole milk into a frothing pitcher. Steam using a steam wand, angling the pitcher so the milk spins in a spiral. Stop when the outside of the pitcher feels hot to the touch and the milk reaches 65 C / 150 F on an instant-read thermometer. The surface should look glossy and smooth, not bubbly.

If using a handheld frother, heat the milk in a small saucepan over medium heat until it just begins to steam (about 65 C / 150 F), then froth for 20 to 30 seconds.

Pour the steamed milk slowly over the chocolate-pepper base, holding back the foam slightly with a spoon, then spoon the foam on top.

Dust the surface with a pinch of Dutch-process cocoa powder through a small sieve. Serve immediately.