First, make the crust. Preheat the oven to 350 degrees. Place the dates in the bowl of a food processor and pulse until small granules form. Don't overmix or they will turn into a paste. Add the shortening, arrowroot, and sugar, and pulse until combined into a crumbly mixture. If it is too sticky, add some arrowroot powder one tablespoon at a time.
Place the mixture in the bottom of a 9-inch tart pan. Use your hands to work the mixture evenly across the bottom and up the sides, pressing it into an even form. Bake for 15 minutes, or until lightly browned - crust will be slightly soft, but develop a firmer texture as it cools. Set aside to cool to room temperature, or about 1 hour.
When the crust has fully cooled, make the filling. Sprinkle the turmeric and gelatin on the lemon juice and set aside for 5 minutes to bloom.
Add the shortening and sugar to a saucepan and heat on low to melt and dissolve. Take off the heat and allow to cool a bit before adding the lemon juice, turmeric, and gelatin mixture.
Stirring constantly with a whisk, heat on the lowest setting until the mixture is lukewarm and all of the fat, sugar, and gelatin are dissolved. Your mixture should be viscous. Take care not to overheat the mixture as it will cause the gelatin to overcook. Take off the heat and set aside.
In a small bowl, first whisk together the orange juice and arrowroot powder and then add to the pan with the lemon mixture.
Place the pan with the filling on low heat and cook, stirring constantly with a whisk, until just thickened, about 5 minutes. You'll notice the texture of the mixture change from fully viscous to the texture of thin pancake batter. Do not overcook. When the mixture has thickened, pour immediately into the tart crust.
Allow to cool for 5-10 minutes before placing in the refrigerator for at least 2 hours to set.
Notes
This recipe does fantastic prepared ahead of time, and keeps wonderfully in the refrigerator.
Recipe by Autoimmune Wellness at https://autoimmunewellness.com/citrus-tart/