In a medium sauce pan cook blueberries and water on medium low until slightly boiling.

Smash up the berries to extract more juice.

After about 10 minutes of cooking, strain the berries in a mesh strainer.

Reserve the juice and discard the pulp.

Return the juice to the pan and add the sugar and eggs.

Cook on low for about 15 minutes. Slowly add in the butter, a tablespoon at a time, until melted. Cook for approximately 15 minutes more (on medium) or until the mixture has thickened and coats the back of the spoon.

Once cooked, remove from heat and store it in a heat proof container.

Preheat the oven to 350 degrees.

Generously grease your mini cupcake pan with nonstick spray.

In a mixer fitted with a paddle attachment, blend butter and powdered sugar.

Add in flour, salt, and extract, mix until just combined.

Scoop 1 in balls into each mini muffin cup. Cook for 6 minutes.

Remove and make an indentation with the back of a spoon.

Spoon a 1 teaspoon of the blueberry filling and return to oven.

Bake for another 8 minutes. Allow to cool and sprinkle with powdered sugar.