Combine cream, basil and erythritol, or sugar, in a medium saucepan over medium heat.
Bring to a boil, then remove from heat and let steep for 30 minutes.
Pour through a fine-mesh sieve into a bowl to remove solids.
Press on solids to release as much flavor and liquid as possible.
Lightly grease six 3/4 cup ramekins or custard cups.
Pour 1/2 cup of the almond milk or whole milk into another medium saucepan.
Sprinkle gelatin over and let sit 3 minutes.
Add the remaining almond or whole milk and set over medium heat, stirring constantly.
Cook until the gelatin dissolves and steam begins to rise from the milk, but do not boil.
Remove from heat and gently stir in the cream and stevia, if using.
Divide the mixture between prepared ramekins and cover with plastic wrap.
Refrigerate until chilled and set, about 4 hours.
Serve in the cups or unmold onto plates.
To unmold, sit the bottom of each ramekin in hot water for 30 seconds. Run a sharp knife around the inside of each ramekin to loosen and flip out onto the plate. I found it took a little jiggling to get the panna cotta to come free.
Top with your favorite berries and serve.
Notes
*Erythritol is a naturally-occurring sugar alcohol found in fruits and fermented foods. It is a popular sweetener for diabetics as it has little effect on blood sugar.