Prepare molds by coating them with oil and wiping any access off thoroughly, if you plan to unmold the panna cotta. Alternatively, you can skip the oil and serve panna cotta right in the cups, it makes it very simple. Use anything you have on hand - small ramekins, ice cream cups, whisky glasses, etc. Today, I used this Nordic Ware mini bundt pan.

Combine 2.5 teaspoons gelatin with 2 tablespoons water in a small dish. Leave to bloom while working on the rest.

Combine 1/3 cup sugar, vanilla and 1 cup milk (or cream) in a medium sauce pan. Warm until sugar dissolves.

Add gelatin (it will be a thick pancake). While whisking, warm until gelatin dissolves. Remove from heat.

Add remaining 1 cup of milk or cream, and whisk well. This will cool down the mixture so we don't affect the probiotics in kefir.

Add kefir to milk/gelatin mixture, whisk well to make sure no grains remain. Shaking works best, if you feel like washing one more dish.

Add juice of 1/2 lemon.

Pour into prepared molds, and refrigerate until firm, at least 3 hours and better overnight.