Lightly grease 6 ramekins (4–6 oz each) or small dessert glasses with a neutral oil or cooking spray. If you plan to serve panna cotta directly in the glass without unmolding, skip the greasing entirely.

In a small mixing bowl, sprinkle the 2 ¼ tsp unflavored gelatin evenly over the 3 tbsp water. Let it sit undisturbed for 5 minutes to bloom (it will look lumpy and spongy — that's correct). Do not stir.

In a medium saucepan, combine the 2 cups heavy cream, 1 cup milk, ⅓ cup sugar, 1 pinch of fine salt, and 1 whole vanilla seeds and pod (if using). Heat over medium heat, stirring occasionally, until the ⅓ cup sugar has fully dissolved and the mixture just begins to steam and simmer around the edges — do not let it boil. This takes about 4–5 minutes.

Remove the saucepan from the heat. Add the bloomed 2 ¼ tsp unflavored gelatin to the hot 2 cups heavy cream mixture and whisk immediately and thoroughly until the 2 ¼ tsp unflavored gelatin is completely dissolved, about 1–2 minutes. There should be no visible 2 ¼ tsp unflavored gelatin granules remaining. Add the 1 tsp vanilla extract and stir to combine.

If you used a 1 whole vanilla, fish out and discard the pod. For the smoothest result, pour the mixture through a sieve into a large measuring cups or pitcher (Large) — this catches any undissolved 2 ¼ tsp unflavored gelatin or 1 whole vanilla pod bits and makes it easy to pour into the ramekins.

Let the mixture cool for about 5 minutes at room temperature, then carefully ladle or pour it evenly into your prepared ramekins, filling each about three-quarters full.

Let the ramekins cool to room temperature (about 20 minutes), then cover each loosely with plastic wrap and refrigerate for at least 4 hours, or overnight. The panna cotta is set when it no longer jiggles like liquid — it should have a gentle, uniform wobble all the way through, like firm Jell-O.

Combine the 2 cups mixed berries, ⅓ cup sugar, and 1 tbsp lemon juice in a small saucepan over medium heat. Cook, stirring occasionally, until the 2 cups mixed berries break down and the sauce thickens slightly, about 8–10 minutes. Taste and adjust ⅓ cup sugar as needed. For a smooth coulis, press through a sieve. Let cool, then refrigerate until ready to serve.

To unmold, run a thin knife or small offset spatula around the edge of each ramekins to loosen the panna cotta. Place a serving plate face-down on top of the ramekins, then confidently flip both together and give a gentle shake. The panna cotta should release cleanly. If it sticks, briefly dip the bottom of the ramekins in warm water for 5–10 seconds, then try again.

Spoon 2 cups mixed berries coulis around the base of each panna cotta, scatter fresh mixed berries on top, and add a sprig of mint if desired. Serve immediately, or keep refrigerated for up to 4 days.