Preheat the oven to 200 degrees Celsius.
Line the bottom two 10/12 cm or one 16 cm spring form, and line or grease the sides.
Chop the pistachio nuts roughly, add to a bowl together with the rest ingredients for the crust. Pinch together using you hands until you have a fairly firm dough. Add a bit more coconut oil or applesauce if the dough doesn't come together.
Transfer the dough for the crust to the spring forms/form and press down using a small glass or measuring cup.
Combine the diced rhubarb with sweetener and cinnamon in a bowl, stir to combine. Spread evenly over the crust. Place in the oven and bake for approximately 8-12 minutes, until it start to turn golden brown and the rhubarb has softened.
Meanwhile prepare the cheesecake layer by adding the crumbled goat cheese to a bowl and beat using a hand mixer, or use stand mixer if preferred. The goat cheese should be fairly but not completely smooth.
Next add the cream cheese and beat again, until the two are combined and turned smooth. Then add Greek yogurt and beat again, until smooth. Mix until well combined but do not over beat or you'll incorporate too much air. Stop and scrape the sides as needed.
Add the sugar, mix again until incorporated the cheesecake mixture.
Add the egg and whisk gently by hand or on low speed just until combined. Scrape the sides again making sure the cheesecake batter is well combined.
Remove the cheesecakes crust from the oven, turn down the heat to 165 degrees Celsius and bake in the middle of the oven for 20-25 minutes, or until the edges are lightly golden and the middle still is a bit wobbly. Make sure to keep an eye on the cheesecakes making sure you don't bake it for too long so it turns out dry. Turn the oven off, slightly open the oven door and leave the cheesecakes inside for 20-30 minutes. Remove the cheesecakes, run a knife around the edges gently. Let cool for 30-45 minutes in room temperature. Cover the cheesecakes and place in the fridge, let them cool for at least 4-5 hours, but preferably overnight.
This part can be done in advance or just before serving: Preheat the oven to 200 degrees Celsius. Place the cut rhubarb stalks in an oven safe baking dish. Add sugar and lemon juice, toss together. Cover with foil and bake in the oven for 15-18 minutes. Remove the foil, give it a stir and bake for 3-6 minutes more. The juices and sugar should have turned slightly syrupy, the rhubarb should be tender but not mushy or be falling apart.
Remove the cheesecakes from the fridge about 30 minutes before serving.
Top with the roasted rhubarb and roughly chopped pistachio nuts.