Preheat the oven to 375 F and line a baking sheet with parchment paper lightly greased with avocado oil.
Portion out the crab and use a fork to break up any large chunks. The meat should be fine. Combine the crab meat, sweet potato, flours, and seasonings (reserving about 1 tsp green onion for topping) and mix well until combined.
Add the lemon juice, avocado oil, and egg (see notes for gelatin egg) and mix well.
Form the mixture into uniform crab cakes (you should have about 8) and place on the greased baking sheet.
Bake in the oven for 25 minutes (or until crispy), carefully flipping about halfway through.
Remove from the oven and allow to cool slightly before topping with horseradish avocado mayo (see below) and green onion.