Start by soaking the gelatin leaves in a bowl of cold water for 5 minutes to bloom them—this allows the gelatin to absorb water and dissolve smoothly later. While the gelatin soaks, combine the heavy cream, milk, sugar, vanilla bean (split lengthwise to release the seeds), and salt in a saucepan. Heat this mixture over medium heat, stirring occasionally, until it's steaming hot but not boiling—you want the sugar fully dissolved and the vanilla flavor infused, which takes about 5-7 minutes. I find that letting the vanilla bean steep for a minute or two after removing from heat really intensifies the flavor before you strain it out.

Remove the hot cream mixture from heat and let it cool for about 1 minute. Squeeze the excess water from the bloomed gelatin leaves and stir them into the hot cream until completely dissolved and smooth. Pour the mixture through a fine-mesh strainer to remove any vanilla bean pieces and ensure a silky texture. Divide the strained liquid evenly among 6 serving glasses or ramekins, then transfer them to the refrigerator to chill for at least 3 hours, or until the panna cotta is set and jiggles just slightly when gently shaken.

While the panna cotta chills, prepare the strawberry topping. Combine the hulled and sliced strawberries, cornstarch, sugar, and lemon juice in a saucepan over medium heat. Stir gently and cook for 4-5 minutes until the strawberries begin to release their juices and the mixture thickens slightly—the cornstarch will turn the juices glossy and create a light sauce rather than a watery puddle. I like to keep some strawberry pieces slightly firm, so I don't overcook this; you want a compote, not a jam. Remove from heat and let the strawberry mixture cool to room temperature before spooning it over the set panna cotta.

Once the strawberry compote has cooled, spoon it generously over each set panna cotta, allowing some of the glossy strawberry juices to pool on top. Return the glasses to the refrigerator for at least 30 minutes before serving—this allows the flavors to meld and the dish to be perfectly chilled. Serve cold, and remember that panna cotta is best enjoyed within a day or two for the best texture and flavor.