Place all berries, separated in a single layer, on two baking-paper lined trays; freeze for 30 minutes.
Process Natvia in a spice grinder until consistency of icing sugar.
Combine yoghurt, powdered Natvia, vanilla seeds and 1/3 cup of the pistachios in a medium bowl. Add 1/2 cup of the frozen raspberries to the bowl, crush against the side of the bowl with a wooden spoon; mix well.
Using a toothpick, dip frozen berries, one at a time into the yoghurt mixture. Gently shake off excess yoghurt and place berries on lined trays, making sure they don’t touch; remove toothpicks. Freeze coated berries for 3 hours until coating is set. Cover remaining yoghurt mixture; refrigerate.
Repeat, dipping coated berries in remaining yoghurt mixture for a second coat; lightly sprinkle with remaining pistachios. Freeze for 4 hours or overnight until frozen. Store in an airtight container in the freezer for up to two weeks.
Nativia is sweetener made from Stevia and Erythritol.Test Kitchen tip