01 - Preheat oven to 325°F.
02 - In a saucepan, heat the heavy cream and vanilla bean over medium heat until just simmering. If using vanilla extract, add it after heating. Remove from heat and let steep for 10 minutes.
03 - In a large bowl, whisk together egg yolks, granulated sugar, and salt until pale and slightly thickened.
04 - Slowly pour the warm cream into the egg mixture, whisking constantly to avoid curdling. Strain the mixture through a fine-mesh sieve into a pouring jug.
05 - Divide the custard evenly among 4 ramekins. Place ramekins in a deep baking dish.
06 - Fill the baking dish with hot water halfway up the sides of the ramekins to create a water bath.
07 - Bake for 35 to 40 minutes, or until custards are set but still slightly wobbly in the center.
08 - Remove ramekins from the water bath, cool to room temperature, then refrigerate for at least 3 hours or overnight.
09 - Before serving, sprinkle an even, thin layer of granulated sugar over each custard.
10 - Caramelize the sugar with a kitchen torch or under a broiler until golden and crisp. Allow the brûlée to cool for 1 to 2 minutes so the sugar hardens.
11 - Top each crème brûlée with fresh mixed berries. Dust with powdered sugar if desired. Serve immediately.