Preheat oven to 325°F (160°C). Place four 6-ounce ramekins in a deep baking dish and set aside.

Heat the heavy cream in a medium saucepan over medium heat until small bubbles form around the edges, about 4-5 minutes. Remove from heat, stir in the rose petals, cover, and let steep for 20 minutes.

Strain the cream through a fine-mesh sieve into a clean bowl, pressing gently on the petals to extract all liquid. Discard the petals and return cream to low heat to keep warm.

In a medium bowl, whisk together the egg yolks, 1/3 cup sugar, vanilla extract, and salt until smooth and pale yellow, about 1 minute. Slowly pour the warm cream into the egg mixture while whisking constantly to prevent curdling.

Strain the custard mixture through a fine-mesh sieve into a large measuring cup or bowl with a spout. Divide evenly among the prepared ramekins.

Pour hot water into the baking dish until it reaches halfway up the sides of the ramekins. Carefully transfer to the oven and bake for 35-40 minutes, until the custards are set around the edges but still jiggle slightly in the center when gently shaken.

Remove ramekins from the water bath and let cool to room temperature, about 30 minutes. Cover each with plastic wrap and refrigerate for at least 4 hours or overnight.

Just before serving, blot any moisture from the surface of each custard with a paper towel. Sprinkle 1-1½ tablespoons superfine sugar evenly over each custard in a thin layer.

Using a kitchen torch, hold the flame 2-3 inches from the surface and move in circular motions until the sugar melts and caramelizes to a deep amber color. Let stand for 2-3 minutes to harden before serving.