For the butter crust: place the flour, sugar, and salt into a food processor, along with the ice cold butter. Pulse for a few minutes until mixture resembles fine crumbs. Slowly add in the cold water and continue mixing until dough comes together to form a ball, about 30 seconds. Turn dough out onto lightly floured work surface and knead the dough into a smooth ball; don't overwork the dough. Cover with plastic wrap and place into refrigerator for at least 1 hour.

Preheat the oven to 350F. Meanwhile, prepare the filling. In a large bowl, toss together the blueberries, sugar, cornstarch, cinnamon and lemon juice. Stir until berries are coated.

Roll out the chilled dough into large rectangle; the dough needs to be on the thin side. Use a 2 1/2 inch cookie cutter or glass/cup to cut out small circles. Drop dough circles into mini-cupcake tins; I used a 24-count pan. Using your fingers or the bottom of a shot glass, press the dough into the bottom and sides of tin. Top with a generous and overflowing amount of blueberries.

Bake the mini tarts at 350F for 25-30 minutes, or until the edges of the tarts turn a golden brown color. Remove the tarts from the pan, using a spoon, onto a cooling rack to cool completely.

Once cooled, drizzle the top with melted white chocolate. I used the microwave to melt mine and placed the chocolate into a zip-lock bag, then cut off a tiny tip off the edge.