Frozen yogurt with blueberry jam

Steps

1. Prepare the base: In a bowl, mix together the yogurt, honey (or powdered sugar), and vanilla, if using. Taste and adjust the sugar to your liking.
   
2. Fill the jars: Place a spoonful of blueberry jam at the bottom of each small jar. Add the yogurt mixture on top, filling to the top. For a marbled effect, you can mix lightly with a chopstick or spoon.
3. Freezing: Smooth the top, add a small stick if you want to remove them from the molds like popsicles (optional). Place in the freezer for 3 to 4 hours, until set but not too hard.
   
4. Enjoy: Let stand at room temperature for 5 minutes before eating to make them creamier. Serve as is or with a few fresh blueberries on top for a wow effect.