What is a cake in a jar?

A cake in a jar is exactly what it sounds like — a layered dessert built inside a reusable glass jar, with all the elements of a proper cake packed into a portable, single-serve format. No fork required, no plate, no fuss.

At Frostella, we've taken the concept seriously. Our 500g glass jars with metal twist lids layer fluffy handmade sponge with our signature silky buttercream and slow-cooked artisanal fillings. The result is something that looks elegant, travels beautifully, and tastes every bit as good as anything from a specialist bakery.

Why Frostella is different

Most dessert products — even premium ones — lean on pre-made fillings, artificial flavourings, or shelf-stable shortcuts. Frostella doesn't. Here's what's inside every single jar:

• The sponge: Light, airy, and made from scratch with traditional flour, natural cane sugar, and British farm eggs. Not a mix.
• The buttercream: A genuine Swiss meringue buttercream — pure butter, fresh egg whites, sugar, and natural vanilla extract. Velvety, never too sweet, never greasy.
• The fillings: Every preserve and curd is slow-cooked in-house. No pre-made jars from a supplier. No shortcuts.
• No artificial colours or preservatives. Just honest ingredients and the natural vibrancy they bring.

Choose your 500g jar

Each flavour is crafted as its own recipe, not a variation on a base. The filling, the buttercream blend, and the sponge balance are all calibrated to make each one stand on its own.

The ideal gift — or a very good reason to treat yourself

Cake in a jar travels far better than a slice on a plate. Whether you're sending a sweet surprise to a friend, adding something special to a hamper, or simply rewarding yourself after a long week, Frostella jars are an easy, thoughtful choice.

And the jar itself is worth keeping. Our 500g glass jars are fully reusable and recyclable — perfect for storing spices, overnight oats, jams, or anything else that deserves a beautiful home once the cake is gone.

How to enjoy your jar

For the cleanest, most defined layers, eat straight from the fridge. If you prefer a softer, more indulgent texture, let it sit at room temperature for 15–20 minutes first — this lets the organic butter in the buttercream bloom back to its signature velvety consistency.

Either way: long spoon, straight through the layers. There's no wrong technique.

Storage tips

Keep refrigerated and consume within 7 days with the lid sealed. Frostella jars are also suitable for freezing for up to 3 months — thaw overnight in the fridge and allow to reach room temperature before eating.