Cakes dome, crack and sink for three different reasons

The points below about cake faults are ordered by how much difference they make, not by how often they get repeated.

Doming is an edge and centre problem

The edges of a cake tin heat first, so the batter there sets while the middle is still liquid and rising. The still-liquid centre continues to expand upward, producing the peak.

Lowering the temperature slightly and baking longer narrows the gap between edge and centre. Insulating the tin sides, whether with a purpose-made strip or a damp cloth band, works on the same principle.

Cracking is a crust that set too early

A hot oven dries and sets the top surface before the cake has finished expanding beneath it. The expanding interior then splits the crust, which is a fault in a sponge and a signature in a loaf cake. The remedy is again a lower temperature, or covering loosely once the top has coloured.

Thick batters in narrow tins crack more, because the rise has further to go through a smaller opening.

Sinking is a timing failure

A cake sinks when the gas structure expands and then collapses before the batter has set firm enough to hold it. Too much leavening produces large bubbles that rise and burst rather than a fine even crumb.

The part that matters: opening the oven early drops the temperature and can collapse a structure that had not yet set. Underbaking has the same effect, since the middle never firms and falls once it cools.

Dense and heavy is usually air

Creaming butter and sugar mechanically incorporates air, and that air is a substantial part of the rise. Butter that is too cold will not aerate, and butter that is melted cannot hold air at all.

A split batter, usually from cold eggs added too quickly, loses the air that was already there. Overmixing after the flour goes in develops gluten and squeezes air out at the same time.

Dry is nearly always overbaked

Cakes continue cooking after they leave the oven, so a skewer that comes out perfectly clean often means slightly too long. A few moist crumbs on the skewer is the better signal for most sponges.

Nine times out of ten, reducing sugar dries a cake more than people expect, because sugar holds moisture in the crumb. Fan settings dry surfaces faster, which is why many bakers turn the fan off for delicate cakes.

Ovens, pans and produce vary — trust what you can see and hear over any timing.

Change one thing at a time

Baking faults have overlapping causes, and altering three variables at once teaches you nothing. Writing down what you changed and what happened turns a series of attempts into a method. Tin size matters more than most recipes admit, since a different depth changes the whole bake.

If a recipe fails repeatedly and reliably, an oven thermometer is a more likely explanation than the recipe.

Everything above, in order of what to do first

1. Doming is an edge and centre problem. The edges of a cake tin heat first, so the batter there sets while the middle is still liquid and rising.
2. Cracking is a crust that set too early. A hot oven dries and sets the top surface before the cake has finished expanding beneath it.
3. Sinking is a timing failure. A cake sinks when the gas structure expands and then collapses before the batter has set firm enough to hold it.
4. Dense and heavy is usually air. Creaming butter and sugar mechanically incorporates air, and that air is a substantial part of the rise.
5. Dry is nearly always overbaked. Cakes continue cooking after they leave the oven, so a skewer that comes out perfectly clean often means slightly too long.
6. Change one thing at a time. Baking faults have overlapping causes, and altering three variables at once teaches you nothing.

The takeaway

Read the fault, change one variable, and write down what happened.

The good version is the one you can make on a Wednesday.