If you’re after a cake that gets laughs the second it hits the table, this “Old Fart” whoopie cushion cake is it. It’s cheeky, surprisingly easy, and perfect for milestone birthdays or anyone with a sense of humour.
This version is made with two cakes stacked, covered in buttercream, then finished with fondant. To nail that classic whoopie cushion shade, I slowly mixed pink + purple food colouring until it looked right, then topped it off with edible letters.
What You’ll Need
Cake + icing
- 2 round cakes (same size – chocolate or vanilla)
- Buttercream frosting (enough to fill + crumb coat)
- Cake board (optional, but makes decorating easier)
Decorating
- Fondant (enough to cover the whole cake)
- Pink food colouring (gel is easiest)
- Purple food colouring (gel is easiest)
- Edible letters (for the message)
- Icing sugar or cornflour (for rolling)
Helpful tools (optional)
- Offset spatula
- Bench scraper or cake smoother
- Fondant smoother (or just clean hands)
- Small sharp knife or pizza cutter (to trim fondant)
Step-by-Step: How to Make the Whoopie Cushion Cake
1) Stack the cakes
Place your first cake on a board or plate. Spread a generous layer of buttercream on top, then place the second cake directly on top.
Tip: You don’t need to carve a perfect shape. A slightly rounded, imperfect look actually helps it resemble a real whoopie cushion.
2) Buttercream crumb coat
Cover the entire stacked cake with an even layer of buttercream. This locks in crumbs and gives the fondant something to stick to.
Chill the cake for 15–30 minutes (or until the buttercream feels firm to the touch).
3) Mix the whoopie cushion fondant colour
To get that classic dusty whoopie cushion tone, start with pink and add tiny amounts of purple slowly, mixing thoroughly each time.
- Start with pink, knead well.
- Add a small dot of purple, knead again.
- Repeat until the colour looks right.
Tip: Go slowly. Purple is powerful and it’s much easier to darken the fondant than to fix it if you add too much.
4) Cover the cake with fondant
Dust your surface lightly with icing sugar or cornflour, then roll out your coloured fondant into a circle large enough to drape over the cake.
Lift the fondant carefully and drape it over the cake. Smooth from the top down, easing out any air bubbles as you go. Trim the excess around the base.
Tip: Don’t stress about a few tiny dents or imperfections. Slightly “soft” fondant actually looks more realistic for a whoopie cushion cake.
5) Make the valve
Use a small piece of leftover fondant to create the whoopie cushion “valve”. Roll it into a short tube shape, gently flatten one end, and attach it to the cake with a dab of water.
6) Add edible letters
Arrange your edible letters on top to spell out your message (e.g. “OLD FART 40!”). Press them down gently so they sit securely on the fondant.
Tip: Keep the message simple and bold – the joke is the hero.
Easy Variations
- Change the age: 30, 40, 50, 60… it works for any milestone.
- Swap the message: “Over the Hill”, “You’re How Old?!”, “Still Got It”.
- Change the colour: Try a deeper red, purple-ish mauve, or even a classic rubbery beige tone.
Quick Tips for a Great Finish
- Chill the cake after the crumb coat so the fondant sits smoothly.
- Use gel colours (less sticky, more concentrated).
- Keep the fondant colour muted rather than bright for a realistic whoopie cushion look.
- Don’t overwork the fondant – warmth from hands can make it too soft.
This “Old Fart” whoopie cushion cake is one of those designs that looks impressive, but is actually very beginner-friendly. Two cakes, buttercream, fondant, and a few cheeky edible letters – that’s all you need for a guaranteed laugh (and a very happy birthday crowd).
Looking for some other fun ideas? Check out this classic Dolly Varden cake, or this DIY Flamingo Cake.
