Put the blueberries, thyme, lemon juice and a teaspoon of water into a pan and bring to the boil. Simmer for 10 minutes until the fruit is very soft.
Remove from the heat and push the fruit through a sieve set over a bowl to extract as much juice as possible.
Put the butter, sugar, vanilla extract and blueberry juice into a pan and heat until the butter has fully melted. Then remove from the heat and let the mixture cool down slightly before adding the beaten eggs.
Return to the heat and keep stirring for 20 – 25 minutes until thickened. The mixture will thicken further once cooled down. I prefer to strain through a sieve once thickened just to remove any lumps.
Whip the cream until soft peak stage. Add the blueberry curd to the cream (reserving some curd for decoration) and mix well.