Filipino Leche Flan

Put the Sugar in a heavy pan with 2 tbsp Water and set it over medium heat. Let the sugar dissolve without stirring; once it bubbles, swirl the pan. Cook until it turns a deep amber, about 7 min, and pull it a shade darker than you think you want. Kill the heat and stand back as it darkens to mahogany. Hold the hot caramel pan off the heat, add the Calamansi juice and stir once; the caramel will hiss and stiffen slightly. Divide it between your llanera moulds or one shallow dish, tilting each so the caramel coats the base and climbs a little way up the sides. Set them aside to firm.

⚠ Tip: A gram of sugar on the edge of the pan tells you the colour. Take it to amber, not black; bitter caramel ruins the whole flan.

⚠ Tip: Caramel on the walls gives you the streaks of sauce that run down the flan when it is turned out.

Separate 10 Egg yolks into a wide bowl and leave the whites for another use. Slip the yolks through your fingers to catch the chalazae so nothing stringy goes in. Add Sweetened condensed milk and Evaporated milk to the yolks, then Vanilla extract. Whisk in slow circles by hand until the mixture is one even colour, a couple of minutes; do not beat air into it. Stir through the Lemons if using.

⚠ Tip: One drop of white in the yolks will leave you with a lumpy custard. Separate over a second bowl, not over the yolks.

⚠ Tip: Foam on top means bubbles baked into the finished custard. Let the mix stand for ten minutes and the bubbles rise out.

Pour the custard through a fine sieve into the caramel-lined moulds, passing it through twice if you can spare the time; it should look like heavy cream. Leave about a finger's width at the top so it can set.

⚠ Tip: Straining is what makes the difference between good flan and glass-smooth flan.

Cover each mould tightly with foil, crimping it right over the rim so steam cannot drip in and dot the surface.

Set the moulds in a wide pan and add hot water to come halfway up their sides. Cover the pan, bring to a bare simmer over low heat and steam until the custard is just set, about 40 min. The centre should still wobble like a soft mattress when you nudge the pan; a knife in the middle comes out clean.

⚠ Tip: Fast boiling water makes honeycomb holes. Keep it barely trembling and check early; dry, over-steamed flan goes rubbery.

Lift the moulds out, uncover and cool to room temperature, then refrigerate for at least 6 h; overnight is better. Cold firms the custard so it unmoulds in one piece.

⚠ Tip: Skip the long chill and the flan will slump when you turn it out.

Run a thin knife around the edge of each mould, set a plate with a lip over the top and flip decisively. Lift the mould slowly and let every bit of caramel run down over the custard. Serve cold, sliced into wedges.

⚠ Tip: If it sticks, dip the base of the mould in hot water for a few seconds, never long enough to melt the custard.