Make the crust. Combine the ground gingersnaps, brown sugar and salt in a large mixing bowl and whisk to combine. Add the melted butter and whisk until evenly combined. Press the mixture evenly into a 9-inch tart pan with a removable bottom. Freeze for at least 10 minutes while you prepare the filling.

Make the filling. Whisk together the sugar, lemon juice, lemon zest, cornstarch and water in a medium saucepan. Add half of the blueberries and toss to combine. Cook over medium-high heat, stirring constantly, until the liquid simmers and thickens. Remove pan from the heat. Add the remaining blueberries and vanilla extract and gently toss for 1 minute until evenly combined. (If the liquid seems too thick to coat all of the blueberries, you can add an extra 2 tablespoons of water.)

Chill. Pour the filling immediately into the prepared crust and spread it our evenly. Refrigerate the tart for 1-2 hours or until the filling is set.

Serve. Slice, serve and enjoy!