Cube the tempeh into chunks. (I like to make them about the size of a garlic clove to keep the size consistent across all pieces.)
Set a large pan over medium heat and add the neutral oil. Add the tempeh and pan-fry it until it is very golden and crisp on the top and bottom, 2 to 3 minutes per side. Transfer to a paper towel to drain.
Turn the heat to medium-low. Add the onion to the remaining oil and cook, stirring occasionally, until the onion has softened, 5 to 6 minutes. Season with a pinch of salt. Add the garlic, ginger, turmeric, coriander, cumin, and pepper flakes and cook for another minute or so.
Chop the preserved lemon so finely that it is almost a paste and add it to the pan. Pour in the coconut milk and stir to combine. Season with salt and bring this to a simmer. Simmer this broth until the coconut milk has
reduced by nearly half, 8 to 10 minutes.
Return the tempeh to the pan and give everything a mix to get it all creamy and coated. Taste and season with salt and black pepper, as needed.
In a small bowl, toss the herbs with the preserved lemon brine to make a quick herb salad. You'll have extra curry sauce around the tempeh, so I like to spread a layer on top of the flatbread, making a tempeh pizza of sorts. Top with the lemony, herby salad and eat with a fork and knife.