Refrigerate the batter for 5-10 minutes as you preheat the oven and prepare the ramekins. (No need to cover the batter unless you are refrigerating it for longer than 1 hour. Can be made up to 2 days in advance, see make ahead instructions below.)
Adjust the oven rack to the lower third position and preheat to 400°F (204°C).
Prepare the ramekins: Brush four 6-ounce oven-safe straight sided ramekins with a generous coating of the softened butter. Sprinkle in the granulated sugar, then shake/rotate each to ensure every spot of the ramekin has a sugar coating. Place ramekins on a baking sheet. Discard excess sugar.
Spoon batter evenly into ramekins. Using a knife or icing spatula, smooth down the surface. Run a knife, icing spatula, or your thumb around the rim at the top, creating a “channel” between the batter and the rim of your pan. Feel free to wipe the edges clean with a towel, though I don’t always do that and don’t notice a difference in appearance or rise.
Bake: Place baking sheet with ramekins on top in the oven. Immediately reduce oven temperature to 375°F (191°C). Bake for 13-14 minutes or until the edges are set and the center just barely jiggles when you give the pan a light tap. Avoid opening/closing the oven too much.
Remove from the oven and serve immediately plain or with optional toppings. Soufflés begin to fall within minutes. You’ll still have that sponge-like texture underneath a crackly top, though it settles into a denser texture as time passes. Cover and store leftovers in the refrigerator for up to 3 days.
