In medium saucepan mix lime juice, blueberries, and sugar.

Heat on medium bring to a boil and cook for 2 minutes

Place a strainer over a bowl and stain and press blueberries until all liquid is in a bowl.

Mix eggs into blueberry mixture slowly while whisking constantly until it's all combined.

Return mixture to heat and add in the butter and whisk until it thickens (coats back of a spoon)

remove from heat and let cool