1. For the crust: In a food processor, process pistachios and walnuts until the nuts resemble a small crumble.
2. Then add the rest of the crust ingredients and process until it all comes together. Mixture should stick together.
3. Divide mixture evenly in 2 and press into 2 mini-tart tins. Freeze for 45 minutes.
4. Meanwhile, start preparing the raspberry and rhubarb filling: Drain cashews and process with lemon juice, dates, rhubarb, raspberries, rose water, coconut cream, and salt. Keep processing until the mixture is silky-smooth.
5. Remove the bases from the freezer and top tarts with raspberry and rhubarb mixture. You will find yourself with approximately ¼ cup left of the mixture; you can either enjoy it as is, or leave it for a delicious dessert or breakfast and top it with granola and/or crushed nuts.
6. You might want to decorate the tarts with crushed pistachios, raspberries, blueberries, rose petals ... whatever your heart desires.
7. Place mini tarts in freezer to set for 30 minutes or place them in the fridge for 2 hours.