Ingredients:

  • 1 cup Granulated Sugar
  • 2 Tbsp Fresh Lemon Zest (finely grated zest of 3-4 medium lemons)
  • 2 whole Large Eggs (room temperature)
  • 4 Large Egg Yolks (room temperature)
  • 1/2 cup Fresh Lemon Juice (freshly squeezed)
  • 1/2 cup (1 stick) Unsalted Butter, cut into 1-inch cubes, cold
  • Pinch Fine Sea Salt (optional)

Instructions:

  1. Set up the Double Boiler: Fill a medium saucepan with about 1 inch (2.5 cm) of water. Bring the water to a gentle simmer (medium-low heat). Ensure the simmering water will not touch the bottom of your mixing bowl when placed on top.
  2. Infuse the Sugar: In the heatproof bowl, combine the granulated sugar and the lemon zest. Rub the mixture vigorously between your fingers for 30 seconds to release the essential oils, intensifying the flavor dramatically.
  3. Combine Wet Ingredients: Whisk the two whole eggs and four egg yolks into the sugar-zest mixture until thoroughly combined and slightly pale.
  4. Add Juice and Salt: Slowly whisk in the fresh lemon juice and the pinch of salt until the mixture is uniform.
  5. Place over Heat: Place the bowl over the simmering water. Immediately begin whisking the mixture continuously.
  6. Cook Gently: Maintain a gentle simmer beneath the bowl. Continue whisking steadily for 10–15 minutes, ensuring you scrape the sides and bottom constantly. This prevents the edges from overheating and scrambling.
  7. Watch for Thickness: The curd is ready when it thickens significantly and coats the back of a spoon (Nappe stage). If you run your finger across the coated spoon, the line should hold without dripping. (The curd should reach an internal temperature of 170°F or 77°C).
  8. Strain Immediately: Remove the bowl from the heat immediately. Pour the hot curd through the fine-mesh sieve into a clean, separate bowl. This removes any tiny bits of cooked egg and used zest, ensuring a silky-smooth finish.
  9. Emulsify the Butter: While the curd is still hot, whisk in the cold, cubed unsalted butter, one cube at a time. Whisk vigorously until each piece is fully incorporated and melted before adding the next. The cold butter stops the cooking process and adds shine.
  10. Chill: Pour the finished curd into a sterilised jar or container. Press a piece of cling film (plastic wrap) directly onto the surface of the curd to prevent a skin from forming.
  11. Store: Refrigerate for at least 2 hours, or until fully chilled and firmly set. Store in the refrigerator for up to 2 weeks.