-
Combine the almond flour, tapioca flour, coconut sugar, salt and butter in a food processor, or use a pastry blender in a bowl. Pulse or blend until the texture of coarse meal.
-
In a small bowl, whisk the egg and then add to the dry ingredients. Pulse/mix again until dough comes together. If you’re mixing in a bowl, you may want to use your hands to bring the dough together at the end.
-
Divide the dough into two equal pieces and form into flat, round discs. Wrap each dough disc in plastic wrap. Refrigerate for at least 1 hour or up to overnight.
-
When you’re ready to bake, preheat oven to 425°F.
-
Roll out one round of dough in between two sheets of parchment or on a silicone baking mat into a 12-inch circle. Carefully lay dough into a 9-inch pie dish (not deep dish). If the dough breaks, that’s okay! Just press it back into place and repair any holes/cracks that may have formed. Place in the freezer while preparing the filling.
-
Mix together the rhubarb, strawberries, coconut sugar, tapioca starch, zest and juice of lemon, cinnamon, nutmeg, allspice, salt, and vanilla. Mix well in a large bowl and pour out into chilled crust.
-
Roll out the second round of dough in between two sheets of parchment or on a silicone baking mat into a 12-inch circle. Use a pizza cutter or sharp knife to cut into even 3/4” strips (you can also make them wider, depending on what sort of look you want). At this point, I recommend putting the cut strips back into the refrigerator about 10 minutes to firm back up - it will make them easier to work with and reduce breakage. Use your chilled dough strips to cover the pie with a lattice work crust - I used the method depicted here. Be extra careful when folding the strips - the lack of gluten in the crust makes the dough much more susceptible to breaking, but if it does, just press the strips back into place. Mine broke a fair bit but you can’t tell once it’s baked!
-
Using a silicone pastry brush, brush the crust with the egg white beaten with water.
-
Place the pie on a baking sheet and bake 15 minutes at 425°F. Reduce the temperature to 350°F, and continue baking for 50-60 minutes or until the pie is the pie is golden brown on top and the filling is bubbling. Tent with foil if the pie starts to brown too quickly!
-
Let cool for at least 1 hour before serving. Serve warm or chilled. Keep any leftovers stored in the refrigerator.