In a medium saucepan, whisk together mango puree, sugar, lime zest, egg yolks, whole egg, and salt until smooth.

Cook mixture over low to medium‑low heat, stirring constantly with a heatproof spatula or whisk, until it thickens and reaches about 170 °F (77 °C), thick enough to coat the back of a spoon—this takes about 7–10 minutes.

Remove from heat and stir in chilled butter pieces, one or two at a time, until fully melted and incorporated into a glossy curd.

Immediately strain curd through a fine‑mesh sieve to remove any solids and zest bits, pressing gently to extract.

Transfer to a clean jar or bowl. Place plastic wrap directly on the surface to prevent a skin from forming.

Allow to cool to room temperature, then refrigerate for at least 2 hours (the curd will continue to thicken as it chills).

Use within 2 weeks. Serve on toast, scones, yogurt, crepes, or swirled into desserts.