Place flour, coconut sugar, coconut oil and sea salt into food processor. Blend, pulsing to begin with, for at least one minute, until the flour and sugar change color just slightly as they begin to absorb the fat. The mixture will be powdery, not yet clumping together.
Add optional macadamia nuts and pulse until nuts are in smaller pieces.
Top cake with about half the topping (or a pie with all of it), pressing down slightly so topping sticks to itself. (Reserve any leftover for other uses, such as topping muffin batter before baking!)
Proceed with baking the main recipe.