Preheat your oven to 400 degrees f.
Squeeze the frozen, thawed spinach very well to remove most of the moisture and allow the moisture to drain off your spinach.
Set spinach in a colander until needed.
Heat oil and melt the butter in a large ovenproof skillet. Sauté the onion for about 4 minutes.
Add in the spinach and garlic and continue to sauté for 1-2 minutes.
Stir in the cooked rice, feta, dill, parsley, sea salt, and pepper and remove from heat.
In a medium bowl, whisk the eggs together with the yogurt. Add in a tiny pinch of sea salt and pepper.
Add the beaten egg mixture to the rice in the skillet, and stir well to combine everything.
Transfer to your preheated oven and bake for around 15 minutes, or until the eggs are set and the dish is golden.
Garnish with additional fresh herbs if desired then serve with lemon wedges and an extra dollop of yogurt.