Heat the coconut milk with the lemon peel in a small saucepan over medium heat until it just begins to simmer, then remove from heat and let it steep for 10 minutes to infuse the lemon flavor. While the milk infuses, whisk together the 1 tbsp tapioca, 1 tbsp potato starch, 35g xylitol, and room temperature egg yolks in a bowl until smooth and pale. Slowly whisk the hot lemon-infused milk into the egg mixture, then return everything to the saucepan over low heat. Cook for 3-4 minutes, stirring constantly, until the custard thickens enough to coat the back of a spoon. Remove from heat, strain out the lemon peel, stir in the lemon juice, and transfer to a bowl to cool while you prepare the dough. I like to chill the custard in an ice bath for a few minutes to speed up cooling—it helps you move faster through the recipe.

In a large bowl, whisk together the 75g almond meal, 55g brown rice flour, 40g white rice flour, 55g tapioca, 20g potato starch, 50g coconut sugar, 1/2 tsp baking powder, 3/4 tsp xanthan gum, 1/4 tsp ground ginger, and 1/2 tsp salt. Add the cold cubed ghee and, using your fingertips or a pastry cutter, work it into the flour mixture until it resembles coarse breadcrumbs—this creates the flaky texture we want. In a small bowl, whisk together the egg, 1 tsp vanilla essence, and 65g lactose-free cream, then pour into the dry mixture. Gently knead until the dough just comes together without overworking it. Wrap the dough in plastic and refrigerate for 30 minutes while you preheat the oven and prepare the fruit filling. I find that chilling the dough prevents it from shrinking too much during baking.

Preheat your oven to 180°C (350°F). In a bowl, combine the rhubarb stalks (sliced into 1/2-inch thick pieces), black currants, 1.5 tbsp xylitol, 1 tsp cinnamon, and 1 tsp fresh lemon zest. Toss gently to coat the fruit evenly with the spices and sweetener. Set aside while the dough finishes chilling.

Remove the chilled dough from the refrigerator and divide it into 4 equal portions. Working with one portion at a time, place the dough between two sheets of parchment paper and roll it out into a thin circle about 6-7 inches in diameter. Transfer the circle (still on parchment) to a baking sheet. Spoon about 2 tablespoons of the cooled custard from Step 1 into the center of each dough circle, leaving a 1.5-inch border. Top the custard with a spoonful of the fruit mixture from Step 3. Fold the edges of the dough up and over the filling, creating a rustic galette shape with the center slightly exposed—it's okay if it looks imperfect, that's part of the charm of a galette.

Brush the folded dough edges of each galette lightly with water or a bit of beaten egg to help them brown. Bake at 180°C for 24-26 minutes, until the pastry is golden brown and the fruit is bubbling slightly at the edges. Remove from the oven and allow the galettes to cool for 10 minutes on the baking sheet before serving. I've found that letting them rest briefly makes them hold together better when you plate them.