01 Place a bowl over a prepared ice bath; set aside. Place egg yolks in another small bowl.
02In a pot, combine whisk sugar, cornstarch, salt. Place pot over medium heat and whisk in milk and vanilla. Be sure to constantly whisk the bottom of the pot so the custard does not burn. Once the custard begins to bubble, remove pot from heat.
03Ladle a spoonful of the warm custard into the dish with the egg yolks and whisk to combine and temper the eggs. Add a second spoonful and combine. Pour the egg yolk mix back into the pot with the rest of the custard and stir. Place the pot back on the heat for two to three minutes and continue to stir. Remove the custard from the heat and pour into the dish in the ice bath.
04Once the custard is cool, layer crushed gingersnaps, blueberries and custard in the serving containers of your choice.