Preheat oven to 350F°
Combine 1 cup frozen blueberries (keep the remaining berries in the freezer), Sugar and lime juice in a medium saucepan and cook in medium heat until the sugar melt and the berries release its juice.
Mash the blueberries with a fork as you continue cooking it for about 5 minutes.
Stir the cornstarch and water mixture.
Add to the pan and continue cooking over medium-low heat while stirring using spatula scraping the sides and bottom of the pan. Bring to a full boil until the mixture becomes thick.
Transfer to a medium bowl and fold in the remaining berries and the lime zest.
Fill in the prepared tart shell, crumble the scrap dough, scatter on top and drizzle the melted butter.
Into the oven and bake for about 45 minutes, until the crust is well browned and the filling is bubbly.
Set the pan in a cooling rack and let it cool. Although it is tempting to serve and cut as soon as it comes out from the oven the juices will run out and it is difficult to cut if served too soon.
If you want very precise slices, refrigerate until cold then cut into wedges. Serve cold or room temperature.