In a bowl combine yogurt and water and mix until smooth. Add xylitol and chia seeds and mix well. Let the mixture stay in the fridge covered for at least 4 hours or overnight.
Make the Raspberry Coulis:
In a small saucepan over medium heat cook the raspberries and xylitol, mixing continuously until thickened. Break the raspberries with a fork so that the mixture becomes smoother.
Remove from heat and optionally puree the mixture in a food processor and then pass it through a fine sieve (I didn’t do it because I like my raspberries in chunks but if you dislike the seeds, it is an option). Set aside.
Make the vanilla Yogurt:
In a bowl combine greek yogurt, vanilla and xylitol and mix very well until smooth.
Use tall water glasses or small jars to layer the mixtures. Start with the vanilla yogurt: arrange about 1-2 tablespoon on the bottom of the glasses. Arrange on top some of the raspberry coulis: as much as to cover the yogurt. Place about 3-4 tablespoon of the chia pudding on top. Finish with 1 more layer of raspberry coulis and one of vanilla yogurt. Top with berries and ground or chopped walnuts
Yogurt: for the chia pudding if you find yogurt that is not too thick (e.g. Bulgarian yogurt), you won’t need to dissolve it with water. Just mix 1 cup of it with the chia seeds. For the vanilla layer you would need a thick yogurt such as the greek one or strained Bulgarian yogurt.
Sweetener: Instead of xylitol you can use any other powdered or liquid low carb sweetener by choice. If you are not following a keto diet, you can also use maple syrup or honey.
When making the layers, consider that in every glass the proportions of the three mixtures should be around 1: 1: 0,5 (pudding: yogurt: raspberry coulis). Be very careful when layering and smooth out every layer carefully with a teaspoon before adding the next. Leave also some space for the fruits on top.