In a bowl, combine Greek yogurt, honey and vanilla extract.
Cover a baking sheet with parchment paper.
Pour the Greek yogurt over the baking sheet and spread it out equally.
Cover with blueberries, raspberries and walnuts.
Keep in the freezer for about 3 hours. Then, take it out and cut it into rectangles or triangles. Do it as fast as possible to minimize melting. (check notes *)
Put it into food containers while still frozen and keep it in the freezer. (check notes **)
