Heat the butter in a 10-inch nonstick skillet over medium heat, swirling to coat the bottom evenly.
½ tablespoon butter
Gently crack each egg into a small bowl for easy pouring.
2 large eggs
When the butter foams, slide the eggs, one by one, gently into the pan.
For sunny-side up, cook undisturbed until the whites are set and the yolks are runny. This should take around 4 minutes over medium heat, but please go by how the eggs look, not by time.
For over-easy, medium, or hard, when the whites are set, flip carefully (I use two wide spatulas, but you might be comfortable using just one) and cook until the yolks reach your preferred doneness. As a general guideline (but please check for yourself, as this can vary), cook just a few seconds for over-easy, 1-2 minutes for over-medium, and 3-4 minutes for over-hard.
Transfer the eggs to a plate, season them with salt and pepper, and serve. If adding toppings (see the notes section below for ideas), do so immediately, while the eggs are still hot, especially if adding cheese.
Pinch salt, Pinch black pepper
Video
Notes
Seasonings, especially salt, are guidelines - adjust to taste.
I love writing precise recipes, but this is one where you'll need to rely on visual cues more than on exact timing. The same egg can cook faster or slower depending on the pan (especially its thickness) and how hot your stove runs. Electric stoves usually run hotter than gas ones.
Fried eggs become crispy when the pan is hot and the fat is shimmering. For creamy eggs, cook at low heat and use a generous amount of fat.
Choice of fat: Butter adds nutty richness. Extra-virgin olive oil has a clean, fresh flavor. Frying eggs in pesto adds aromatic depth, while chili oil gives them a spicy kick (but can also release chili fumes, so avoid it if you're sensitive). If using pesto, cook the eggs over medium-low heat to protect the delicate sauce from burning.
Optional toppings: Shredded cheese melts into the hot eggs, adding flavor and richness. Bacon bits add crunch and smokiness. Other tasty options include bagel seasoning and sliced avocados.
Please use a truly nonstick skillet. These skillets' coating wears out quickly, so it's best (in my opinion) to buy cheaper skillets and replace them often than to buy expensive ones and try to hang on to them for years. I replace mine annually. A well-seasoned cast-iron skillet also works, but you'll need to use at least a tablespoon of fat (butter is best), and the risk of sticking increases.
Fresh eggs are best because they stay compact in the pan, giving you a better-looking egg. Older eggs are fine, but their whites are looser and spread out more.