If using fresh strawberries, remove the stem, cut in half and hull. If using frozen, just allow to thaw first.
In a saucepan, bring your strawberries and their juices, the balsamic vinegar, the pinch of salt, vanilla, the sprig of thyme and the maple syrup to a boil. Reduce to a syrupy-jam, breaking up the strawberries with a wooden spoon as they cook, about 15 minutes.
When the juices have reduced and the berries start to look like a syrup, you're done! Remove the thyme sprig and discard. Allow the mixture to cool to temperature.
Either smash up the strawberries with your wooden spoon, or process in a blender for a smoother texture. If you want to blend the whole popsicle together, you can add the cream or yogurt to the cooled strawberry preserves and blend. If you want a more swirled effect (as pictured), keep the preserves and the cream or yogurt separate.
To fill your popsicles, start with adding a spoonful of cream at the bottom, and then alternate with layers of jam. Pick up and lightly drop the popsicle molds onto the counter top to help release any trapped air bubbles. Once almost filled (they will have a fill line you should not go above-- it will expand when frozen), use a long spoon or a chopstick to swirl it all around to make the beautiful design.
Tip: we tried yogurt and Marscapone and both were delicious: the yogurt was easier to fill and had a lighter, slightly more sour flavor at the end. The Marscapone was tricky to get into the popsicle molds, but it was super rich and delicious.
Add in the popsicle sticks and allow to freeze till hard (at least 4 hours, or ideally overnight.) Run the mold under warm water to release the popsicle, and enjoy!