Bloom the gelatin. In a small bowl, sprinkle 2 teaspoons unflavored gelatin over 3 tablespoons cold water.
Let it sit for 5–10 minutes until it swells and looks spongy.
Warm the dairy base. In a saucepan, combine 1 1/2 cups heavy cream and 1 cup unsweetened almond milk. Add 1/3 cup granulated erythritol or allulose and a small pinch of salt. Warm over medium-low heat, stirring, until the sweetener dissolves and the mixture is hot but not boiling.
Add vanilla. Remove from heat and stir in 2 teaspoons pure vanilla extract (or 1 teaspoon vanilla bean paste for specks and deeper flavor).
Melt the gelatin. Add the bloomed gelatin to the warm dairy.
Whisk gently until fully dissolved. If needed, return the pot to very low heat and stir just until smooth. Do not simmer.
Taste and adjust. Taste the mixture.
If you prefer a sweeter panna cotta, add a bit more sweetener and stir to dissolve. Balance with a tiny extra pinch of salt if needed.
Strain for silkiness. For the smoothest result, pour the mixture through a fine-mesh sieve into a large measuring cup with a spout. This catches any undissolved bits.
Portion and chill. Divide into 6 small ramekins, glasses, or jars.
Let them cool at room temperature for 15–20 minutes, then cover and refrigerate at least 4 hours, preferably overnight, until set.
Serve and garnish. Enjoy straight from the cups, or unmold by dipping the ramekin bottoms briefly in warm water and inverting onto plates. Garnish with a few berries, a drizzle of sugar-free sauce, or a sprinkle of shaved dark chocolate.