01 -
Combine sliced rhubarb and water in a small saucepan. Stir often over medium heat until the rhubarb releases enough liquid to prevent burning. Bring to a boil, then reduce heat to medium-low, cover, and cook, stirring occasionally, until rhubarb is soft and fully broken down, about 8 to 10 minutes.
02 -
Transfer cooked rhubarb to a blender or use an immersion blender to process until perfectly smooth.
03 -
Allow rhubarb purée to cool briefly in a clean saucepan. Add sugar, eggs, and salt, whisking thoroughly until the mixture is smooth.
04 -
Place saucepan over medium to medium-high heat. Cook, stirring constantly, until the mixture thickens and gently boils. This should take several minutes and the curd will continue to thicken as it cools.
05 -
Remove from heat. Stir in butter and vanilla extract until butter is melted and incorporated. Optionally, for an even smoother texture, pass the curd through a fine-meshed sieve to remove any solids.
06 -
Allow curd to cool, stirring occasionally to prevent a skin from forming. Refrigerate for at least 3 to 4 hours until fully chilled before serving. Store covered in the refrigerator for up to 2 weeks.