Start by slicing and freezing the bananas for at least 1 hour.
Meanwhile you can cook the rhubarb and strawberry compote by placing all the ingredients for it in a small pot. Bring to a boil and then lower the heat and let it shimmer for 15-20 minutes. Shimmer until the water has reduced and you have a quite thick compote. You can vary the thickness by letting it shimmer for different amount of time. Taste to check if more cinnamon, vanilla or sugar is needed. Keep the compote warm or reheat when making the nice cream.
When the bananas are frozen and ready to make the nice cream preheat a nonstick pan over medium heat with some coconut oil.
Add the rhubarb stems, cinnamon and sugar to the pan and let it fry for 6-7 minutes. The rhubarb should soften, get a little browned and warm.
Meanwhile the rhubarb fries add the ingredients for the nice cream to a high speed blender and mix until smooth. You might need to stop and stir a little in the mixer. Taste to check if more vanilla stevia drops are needed, or if you need to add more milk (depending on how thick you prefer your nice cream).
Place the nice cream in two bowls. Top with warm rhubarbs and strawberry compote, sugar and cinnamon fried rhubarb, peanut butter, pistachio nuts and more cinnamon (if using).
Serve immediately.