How to bake a souffle with a flat top?
In theory, to make one of those perfect looking soufflé with a flat top, you have to do two things:
First, "cut out" the batter, by sliding the back of a knife along the edges of the ramekin
Then, gently drag your fingertip along the inner edge of the ramekin, pushing in the batter.
Now we step into the realm of practice and have to face the biggest unknown in baking: the oven.
Not all home ovens are equal, sadly—some heat more from the bottom, some more from the top. The real problem is when the heat is uneven between the left and the right side, due to ventilation or plate defects.
If your oven is well-mannered, then you want to set it to the static mode and bake the soufflé right in the centre of the oven. Some folks suggest using the bottom rack: not with our oven. The middle rack is a safer bet.
If after doing all this your soufflé still came out asymmetric, don't be too hard on yourself. Remember: it's going to be just as good and it goes in the belly!
My souffle didn't grow, or it wasn't spongy enough. What did I do wrong?
Soufflé doesn't use any baking powder. What makes it grow is the egg whites foam creating tiny air bubbles in the dough and displacing the butter upwards as it cooks. The air bubbles are what make the souffle fluffy and "light".
Over the years, we observed that whenever our soufflé didn't grow as expected, it was because:
We waited too long before baking it, resulting in the batter losing its structure.
We over-mixed the foamy whites with the rest of the ingredients.
What you want to do instead is:
Fold in (not mix) the foam into the rest of the ingredients, briefly and with a wide top to bottom circular motion. Folding seven to ten times is all it takes. It may look like you didn't do it enough, but it's ok like that.
Spend as little time as possible between the folding and the baking. Make sure to have the oven preheated and your ramekins greased before you even start folding in the foam.
Basically, you don't want to knock out the air from the batter. Keep it light and bubbly and place those ramekins in the oven ASAP.
Can I store a soufflé away?
The soufflé is one of those desserts you eat on the spot, hot. Just like a lava cake, waiting for it to cool down would strip the dessert of its most precious quality: warm and foamy sponge cake melting in your mouth.
If you baked too many and can't finish them in one go, the best thing to do is to store them in the fridge and consume within two days top.
You may try to quickly reheat them in the oven or have them cold. They won't be as good, but will still make a pretty decent snack.