Step 1

Heat 1 tablespoon oil in a large skillet over medium heat. Break eggs, one at a time, into the pan. Cook until the whites are set but the yolks are still runny, 1 to 2 minutes. Break the yolks with a spatula. Flip the eggs and cook until just done, about 1 minute more. Transfer to a plate and cover to keep warm.

Step 2

Add the remaining 1 tablespoon oil and onion to the pan. Cook, stirring often, until softened, about 1 minute. Add spinach and arugula in batches and cook, stirring, until wilted, about 4 minutes. Add dill, garlic powder, pepper and salt; cook, stirring, for 1 minute more.

Step 3

To assemble sandwiches, place the eggs on the bottom halves of the English muffins. Top each with ¼ cup of the spinach mixture, then sprinkle with 1 tablespoon feta (reserve excess spinach mixture for another use). Serve topped with the remaining muffin halves.