Add ¼ cup of erythritol to a food processor and blend on a high-speed setting until powdered – about 4/5 minutes. Set aside.
Step 2
Whilst the erythritol is blending, add the diced rhubarb to a small pan with the water and remaining erythritol. Bring the mixture to a boil and stir to combine, then reduce to a simmer for 3-5 minutes, until the rhubarb is soft.
Step 3
Strain the water from the rhubarb and mash the fruit lightly with a fork. Set aside to cool.
Step 4
Add the powdered erythritol, whipping cream, cinnamon, ginger and vanilla to the bowl of a stand mixer.
Step 5
Using a whisk attachment, whisk on a high-speed setting until the cream begins to thicken- this may take a couple of minutes. As it starts to thicken, reduce the speed and continue to whisk, forming thick and fluffy peaks.
Step 6
Divide the mashed rhubarb mixture in half and carefully fold one half through the whipped cream.
Step 7
With the remaining half, add a heaped teaspoon to the base of a ramekin or serving glass. Divide the cream and rhubarb mixture evenly between the 4 serving vessels and then top each with the remaining rhubarb. Serve immediately or chill a little before serving.