For an everyday birthday cake, picking a filling is simple: Just think about what tastes good and you're done.
But if you're tackling something more ambitious and need it to hold up like a professional cake, you might need to work a little harder to find the right filling. Here's how to get the results you want — and avoid an epic fail.
DO consider the weather
When it's really hot out, proceed with caution. Custard cream fillings are far too likely to go all melt-y in warm weather; better to go with ganache and ganache-buttercream hybrids instead. (The serious amount of chocolate in ganache acts as a stabilizer.)
Whipped cream and cream-cheese frosting are two more choices to avoid on a steamy day. No one wants to eat a cake smothered in warm white glop.
DON'T overcomplicate your fillings
This is especially true if you're making a carved cake. Steer clear of quirky buttercreams like two-tone, confetti, chocolate chip or fruit-filled. Once you begin carving you don't want to have to deal with anything hard, squishy or potentially messy in between your layers.
DON'T be generous to a fault
Overfilling a cake, especially in warm weather, can cause layers to slide around. You're better off underfilling a teeny bit, leaving a gap around the edge so there's room for the filling to spread out.
DO think about your cake's journey
Consider where your cake is headed and how you're gonna get it there. If there's a significant drive involved, plan accordingly. Preserves, cream cheese, creme patisserie and whipped cream are definite no-nos because they're unstable and slippery.
DO get fruity
Fresh fruit can be your friend, lending structure and support in between your layers. This approach is popular for "naked" layer cakes, but it actually works well for any style.
If you're using strawberries, place even-size, heart-shaped halves in concentric circles. This method will make every bite taste ah-mazing and prevent your cake from drooping in the middle since the strawberries will prop it up.
Blueberries, raspberries, blackberries, caramelized apples, mangoes and passion fruits are also great cake fillers.