Choose ramekins that suit your meal: small individual ramekins for brunch, or larger ones for an appetizer so you can fit several eggs inside. Preheat the oven to 210°C.
Put a small pat of butter in the ramekin and use your fingertip to spread it evenly over the entire inner surface.
Sprinkle a pinch of salt on the bottom of the ramekin and crack the eggs into it.
Crack the eggs gently so as not to break the yolk.
Spread the crème fraîche over the egg whites, then season with salt and pepper.
Place the ramekin in a baking dish half-filled with boiling water (a "water bath") and put the dish in an oven preheated to 210°C for 7 minutes (until the egg white has set).
Notes
Using this method, you can make all kinds of baked egg dishes (with ham, foie gras, salmon, etc.). Personally, I like to add chopped herbs (such as chives or sage, as shown in the photo) and a clove of minced garlic.