Preheat oven to 375 degrees F (190 C). Prepare three mini loaf pans (or a regular loaf pan, or a 9-inch squared baking pan) and spray a thin layer of oil into the pan. (*See Footnote 3)

Add almonds and 1/2 cup sugar into a blender. Pulse until fine.

Add dried dates (or dried plums). Blend until the dried fruit is grated into the flour. Add rice flour. Pulse a few times to mix well.

Combine egg yolks, vanilla, the remaining 1/2 cup sugar, butter, and orange juice (or brewed tea) in a big bowl. Stir to mix well.

Transfer the almond flour mixture into the bowl of egg yolk mixture. Stir a few times until the liquid is just mixed in.

Add egg whites to a separate bowl. Whisk with a hand mixer until the egg whites form stiff peaks. Transfer to the bowl with almond mixture. Fold with a spatula until the egg whites are just incorporated. Do not overdo it.

Pour batter into mini loaf pans, until the pans are eighty percent filled.

If you're making the date flavor, sprinkle cinnamon powder on top.

Bake until cooked through, about 35 minutes. If you use a normal loaf pan, you will need to extend baking time. If the surface of the cake already turns brown but the cake is not cooked through yet, cover the pan with aluminum foil to prevent from burning. Use a toothpick to poke the thickest part of the cake and it should come out clean.

Immediately transfer the cake onto a cooling rack and let cool completely.

You can wrap the cake loosely with baking sheet if serving on the day its cooked.

To serve the cake later, store in an air-tight container at room temperature up to 3 days, or in fridge up to a week.