Preheat oven to 175°C (350°F). Line a 18*24cm baking dish (7*10 in) with parchment paper

Whisk butter and sugar with a hand mixer, then add vanilla and salt. Add flour while whisking until all is incorporated.

Put dough in the baking dish and press it out evenly.

Bake for 25 min until slighlty golden

Heat the blueberries in the microwave then mix in a blender until liquidy then transfer to a bigger bowl.

Zest the limes and squeeze out the lime juice.

Add all remaining ingredients and stir to combine.

Pour the mixture over the crust and bake for 25 min

Let it cool down then place in fridge to cool completely (around 4 hours) or use the freezer if you are in a hurry.

Once it is completely cool you are able to cut it into squares without making a mess