This is a smooth and tasty filling for cake that’s easy to pipe and holds firmly. If you want a looser filling for tarts use 15g cornstarch instead of 25g.

Blueberry Curd

350g frozen blueberries

100g granulated sugar

25g cornstarch

juice of half a lemon

pinch of salt

¼ teaspoon citric acid, optional*

zest of one lemon

113g unsalted butter

Thaw the blueberries and puree them. Put them through a sieve to remove the skin and seeds. There should be about 260g of blueberry pulp and juice.

In a small pot combine the blueberry pulp and juice, granulated sugar, cornstarch, lemon juice, salt and citric acid (if using). Whisk until it is free of lumps. Put over a medium heat whisking and using a rubber spatula alternatively stir and scrape the sides and bottom of the pot until thickened. 

Taste the blueberry curd to see if the cornstarch is no longer chalky. Once the chalk taste is gone cook one more minute. 

Stir in the butter and whisk until glossy.  

A time saver tip is to pour it warm in a piping bag, tie off the end and allow it to cool in the bag. If cooling in a bowl or container top with a plastic wrap directly against the curd to keep a skin from forming. 

To make a looser curd that is more spreadable and looser use 15g of cornstarch instead of 25g.

This works with all berries. 

It can be made vegan by using vegan butter.

*About Citric Acid, I’ve come across it as an ingredient in Middle Eastern recipes. I’ve found I like to add it where lemon juice might make something too wet, or for real, when I don’t want to cut into a lemon when I need just a hint of sour.