Restaurant Basalt

Step 1. Place the sea buckthorn berries in a saucepan with a splash of water. Heat over medium heat until they burst and soften, then puree them with a blender and press through a fine-mesh sieve to extract 150ml of smooth juice.

Step 2. In a heatproof glass or stainless steel bowl, whisk together the sugar, egg yolks, and the whole egg until the mixture is pale and well combined.

Step 3. Gradually stir the sea buckthorn juice and lemon juice into the egg mixture.

Step 4. Set the bowl over a saucepan of simmering water (double boiler), ensuring the bottom of the bowl does not touch the water.

Step 5. Whisk the mixture constantly for about 10-15 minutes, or until it thickens enough to coat the back of a spoon and reaches 170°F (77°C).

Step 6. Remove the bowl from the heat and immediately begin whisking in the cold cubed butter, one piece at a time, until the curd is glossy and smooth.

Step 7. For an extra-fine texture, strain the curd once more through a clean sieve.

Step 8. Pour the curd into sterilized jars and press a piece of plastic wrap directly onto the surface to prevent a skin from forming. Chill in the refrigerator for at least 4 hours to set completely.