Place the pie crust in a pie plate, and line it with parchment paper. Fill with baking beans, dried beans, rice, or white sugar and blind bake to 375F for about 30 minutes, removing the parchment after 15 minutes.

In a saucepan, stir together all of the ingredients for the berry layer. Cook it over medium-low heat, stirring every couple of minutes. If you are using blueberries, smash a few of them with the back of the spoon to create more juices.

Cook for 5-8 minutes, or until the mixture is thick and no longer cloudy. Spoon it into the bottom of the pie crust, and spread into an even layer. Place it in the freezer until it is chilled and slightly icy.

While the berries are chilling, make the custard by beating together the eggs, sugar, salt, and vanilla bean. If using vanilla extract, add it at the end. Beat together until smooth.

Meanwhile, preheat the oven to 350F.

Scald the whole milk over medium heat–this means to bring it nearly to a boil, but not burn it. Allow it to cool for a couple of minutes, then slowly add a cup to the egg mixture while whisking briskly. This will temper the eggs (heat them slowly) so that they don’t cook and leave any rubbery bits in the custard.

Add in the rest of the milk, then carefully spoon the mixture over the berry layer in the pie crust. Cover the edges of the pie crust with strips of foil to prevent them from burning. Place the pie on a rack in the middle of the oven and bake for 50-60 minutes, or until the custard is set. It should still have a wobble (or jiggle, if you prefer) in the middle, but you want it to be set.

After it’s baked, remove the foil strips. Refrigerate the custard pie until chilled through, about 4-6 hours. Serve topped with whipped cream and berries.