Whisk the base: In a medium bowl, whisk together the egg yolks, sugar, cornstarch (if using), and a pinch of salt until the mixture turns pale and slightly thickened, about 1–2 minutes.

Warm the milk: In a saucepan, heat the milk with the cardamom and vanilla over medium heat until it just begins to steam and tiny bubbles form around the edges — do not let it simmer.

Temper the eggs: Slowly whisk a small ladle of the hot milk into the yolk mixture, stirring constantly. Add a few more ladles gradually to prevent curdling.

Cook the custard: Pour the tempered yolk mixture back into the pan with the remaining milk. Cook over low heat, stirring constantly with a wooden spoon, until the custard thickens and coats the back of the spoon (6–8 minutes).

Finish: Remove from heat and stir in the vanilla. If you used whole cardamom pods, strain through a fine sieve to remove the spice pieces and any solids. Taste and adjust with a touch more sugar if desired.

Chill: Divide the custard among ramekins or small bowls. Let cool to room temperature, then refrigerate for at least 2 hours (or up to 2 days) for a firm, sliceable texture. For a softer, comforting dessert, serve slightly warm instead.

Serve: Just before serving, top with your favorite garnishes — pistachios, orange zest, rose petals, or a drizzle of honey — and enjoy the aromatic elegance as the custard melts on the tongue.