Prepare blackberry sauce by cooking the blackberries with lemon juice, sugar, water, and cornstarch.
Mesh them and remove them from heat to let them cool at room temperature.
Blend flour, salt, sugar, nutmeg, cinnamon, milk, eggs, butter, and vanilla to make an even batter. Let it rest at room temperature for 30 minutes.
Heat a crepe pan, toss it with butter, and then pour 1/3 cup of crepe batter.
Cook both sides for 1 to 2 minutes. Repeat the process to make crepe from the remaining batter.
Place a dollop of vanilla ice cream on the crepe and roll it firmly.
Place the crepe in the freezer for 15 minutes.
Top it with blackberry sauce, whipped cream, and powdered sugar while serving.