In a small bowl, mix the Greek yogurt, lemon zest, lemon juice, chopped dill (or parsley), a pinch of salt, and a little black pepper. Taste and adjust. Set aside.

If using sun-dried tomatoes packed in oil, drain and thinly slice them. Thinly slice the red onion and rinse the spinach if needed.

If you like your onions mellow, toss slices in cold water for 5 minutes to take some bite off them.

Heat a nonstick skillet over medium and add olive oil or butter. Add the garlic and sauté for about 20 seconds until fragrant—don’t let it burn.

Add the spinach and cook just until wilted, about 30–45 seconds. Push the spinach to the side.

Crack the eggs into the pan. For folded scrambled eggs: scramble gently with a spatula, folding in the wilted spinach, salt, pepper, and red pepper flakes. For fried eggs: cook until whites are set but yolks are runny, about 2–3 minutes (flip for over-easy if you prefer).

Sprinkle the crumbled feta over the eggs in the last 30 seconds to warm it through and let it soften.

While the eggs cook, toast your English muffins or ciabatta until golden.

Spread a generous spoonful of the lemon-herb yogurt on both halves of the toasted bread.

Layer the bottom with sun-dried tomatoes, then the egg and spinach mixture, and a few onion slices if using.

Add avocado slices or cucumber, if you like, and top with the other bread half.

Press gently, slice, and enjoy warm.