Heat a drizzle of oil in a heavy 8-inch skillet set over medium-high heat.
Cook the onion for 4-5 minutes, until soft but not browned.
In a medium bowl, whisk the eggs with the baking powder, cumin, turmeric, salt and pepper.
Stir in the onion mixture and the fresh herbs.
Heat another drizzle of oil in the same skillet over medium heat.
Pour in the egg and herb mixture, smooth the top, cover and cook for 8-10 minutes, or until the bottom is just set.
Uncover and slide under the broiler, watching carefully for about a minute, until the top is set.
Slide out or invert onto a plate to serve.