Preheat oven to 350F.
Oil a 9“ or 10” pie pan and spread pineapple chunks evenly throughout pan. Set aside.
Place the almonds, ground flax seeds, and tapioca flour in a food processor and process into a meal (the consistency of a very fine crumb – just be careful not to overdo it or it will turn into almond butter).
Add all remaining cake ingredients into the food processor and process to combine until a uniform batter forms (takes just a few seconds). Scoop the batter over the pineapple chunks and use a spatula to even everything out. Sprinkle toppings evenly on top.
Bake for approximately 1 hour and 15 minutes, checking in occasionally to ensure the top of the cake doesn't burn. When done, remove from oven and allow to cool for at least 10 minutes.