First preheat the oven to 175°C. Line a small springform tin (18cm diameter) with parchment paper and if necessary use some coconut oil for the rim.
Mix all ingredients for the base and knead well. Press and spread it evenly in the baking tin creating a 2cm high rim along the springform tin.
Combine the ingredients for the curd layer until no pieces are left. Pour on the base and bake in the oven for about 30 minutes.
Meanwhile you can prepare the rhubarb layer. Simply cut the rhubarb and the dates into chunks. Combine all ingredients (except the corn starch!) in a pot and bring to a boil. Let it simmer for about 10 minutes. Mix the corn starch with some cold water until fully dissolved. As soon as the rhubarb mixture is done remove the pot from the oven and stir in the corn starch water. Set aside to cool down.
When the cake is ready remove it from the oven and let cool down a bit. Then add the last and final layer of rhubarb compote and let cool down fully before placing it in the fridge for a few hours.
Notes
*Instead of ground oats you can go for regular spelt flour or any gluten-free flour you like.**You can use regular sugar, too.***If you want you can substitute the raspberries with frozen cherries or strawberries.