In a small bowl, whisk together the Greek yogurt, maple syrup, and vanilla extract until smooth and well combined. The maple syrup adds subtle sweetness and helps the yogurt coating set slightly firmer in the freezer. Set this mixture aside at room temperature while you prepare the bananas.

Peel the bananas and slice them into 1/2-inch thick rounds using a sharp knife. Line a baking sheet or large plate with wax paper—this prevents sticking and makes cleanup easier. I recommend using a shallow dish or small bowl filled with the yogurt coating rather than dipping directly from a larger bowl, as it gives you better control and ensures even coverage.

Working with one banana slice at a time, dip both sides into the yogurt coating mixture from Step 1, ensuring full coverage. Place the coated slice on the prepared wax paper. Immediately sprinkle the rainbow jimmies over the top while the yogurt is still wet so they adhere properly. Repeat this process with all banana slices, arranging them in a single layer on the paper without overlapping.

Transfer the baking sheet to the freezer and freeze for at least 2 hours, or until the yogurt coating is completely solid and the bites hold their shape. For best results, I like to freeze them for 3-4 hours or even overnight, which gives the coating a firmer texture that's more satisfying to eat. Once frozen solid, you can transfer the bites to an airtight container for longer storage.