Combine all ingredients in the bowl of a blender and grind until very well combined, about 20-30 seconds, stopping to scrape down the sides of the bowl as necessary. Taste and adjust sweetness if needed.
Divide mixture among reusable freezer pop molds. (Or, place four 3-ounce plastic cups onto a plate or a small baking dish and divide the yogurt mixture evenly among them. Place a popsicle stick into the center and place onto a plate or small baking dish to freeze.)
Freeze for 4-6 hours before serving.
Run the mold under warm water to help loosen as needed.
You can use baby kale in this recipe if you prefer instead of spinach.
Use really good tasting fruit. The better the fruit tastes, the less added sweetener you'll need and the better the final result.
Try to use yogurt with a little fat in it. For little kids, fat is essential for brain development and it can also help their energy stay even longer—especially when they are running around outside in warm weather.
Taste the mixture before you freeze it. Since the sweetness of fruit can vary so widely, be sure to taste the blended mixture before you freeze it. This is the only way to ensure that you'll like the taste of the frozen pops.
Blend the mixture really well. This will ensure that there aren't any undesirable flecks of green!
Use nondairy yogurt if needed.
Use blackberries, raspberries, strawberries, or a mix if desired.