This will make a galette for 3 rows of medium sized apples.
Prepare lemon curd on the stove. I low heat warm two eggs, lemon juice and zest, 1 tbsp butter and 1 tbsp flour stirring constantly for a few minutes until flour is fully blended in. I purposefully leave out sugar, but you can add some if you choose. Honey can be added at the end as shine. Let curd cool and refrigerate to help thicken while you prepare the rest of the steps. Save 2 thinly sliced lemons cut in half moons for decoration and taste.
Prepare oat flour: pulse or grind oat into fine flour.
Make the pastry shell: hand blend flours, cold butter, and add enough cold water to create a dough disc. Roll out onto your baking pan and create the pastry shape you like.
Cut two sides of the apple up to the core so you get the arch sides. Cut into thin strips and keep each side intact. Add to the pastry shell along ith lemon slices.
Add cinnamon on top and brush lemon curd throughout your galette.
Bake at 325°F/165°C for about 75 minutes or 350°F/180°C for about an hour until deep golden brown. I usually turn the oven off around the hour mark and leave in oven another 15 minutes.
About 15 minutes before turning off the oven heat, brush honey or syrup on pastry top and sides for additional shine and sweetness.