For the creme brulee: Arrange an oven rack in the middle of the oven and preheat to 325 degrees F. Place four 6-ounce ramekins in a 9-by-13-inch baking dish. Bring a kettle or saucepan with water to a boil.
Bring the heavy cream to a light simmer over medium heat in a small saucepan. Whisk the sugar, salt and egg yolks in a large bowl or measuring cup. Slowly pour the hot cream into the yolk mixture, whisking constantly until it thickens. Stir in the vanilla extract.
Pour or ladle the custard evenly into the ramekins. Carefully pour enough boiling water into the baking dish to come two-thirds of the way up the ramekins, making sure to keep the water out of the ramekins. Bake until the custard is set and firm when shaken, 35 to 40 minutes. Remove the custards and let cool to room temperature on a rack, then chill in the refrigerator at least 1 hour and up to overnight.
For the berry coulis: Add the berries, sugar, lemon zest and juice and mint to a food processor and puree until smooth. Refrigerate until ready to use. Store in an airtight container for up to 2 weeks.
When ready to serve, sprinkle about 1 teaspoon of sugar over a custard. Using a kitchen torch, caramelize the sugar by keeping the flame close to the sugar but moving it constantly to get an even color. Repeat with the remaining custards. Alternatively, sprinkle sugar over all the custards and place on a baking sheet under the broiler for 4 to 5 minutes, depending on your broiler.
Serve immediately with the berry coulis, a few fresh berries and a sprig of mint on top!
Propane gas torches are highly flammable and should be kept away from heat, open flame and prolonged exposure to sunlight. They should be used only in well-ventilated areas. Follow torch manufacturer's instructions for use.