A lightly spiced slice filled with raspberry jam and topped with pink icing and jelly crystals, this gluten free Belgian slice is a delicious twist on the classic Belgian biscuit.

Three stacked pieces of Belgian slice on a rectangular glass plate, with a small jar of raspberry jam in the background and two cake forks in the foreground.

Welcome, once again, to the land (New Zealand) where we name baked goods after other countries, which probably have nothing to do with the baked goods in question.

Today, we are talking about Belgian Slice. This is the slice version of Belgian biscuits, which are spiced biscuits sandwiched together with jam and topped with pink icing and raspberry jelly crystals.

There seems to be no consensus on why these are named after Belgium, other than that they may be named after the Belgian Bun, which, you guessed it, also seems to have nothing to do with Belgium. It’s like “Afghan” Biscuits all over again.

Guys, I really don’t know what else to tell you, other than that this gluten free Belgian Slice is delicious, and you should make it and not even worry about what it’s called, or why.

Overhead image of five pieces of Belgian slice, three on their sides and two upright, on a small rectangular glass plate, with a silver cake server.

The combination of spices and raspberry is delightful, and it’s worth putting this recipe on your baking-tin-filler list.

This is actually the most tested and tweaked recipe I have shared on this website, I’ve been working on it on and off for over a year.

If you’re interested in the backstory (and the lengths I go to in order to perfect these recipes for y’all!), click the drop-down button below. It’s collapsed for all the folk who don’t care and are just here to make slice 😂

A lot of Belgian slice recipes use a dough that is rolled out in two halves and placed into a tin, to allow for the jam layer in the middle. I tried this but wasn’t happy with the texture of the slice – to make the dough firm enough to roll, it was super dry, no matter how many tweaks I made. It was also very fiddly to get into the tin, and I just could not be bothered with that.

I tried making it with a more cakey batter, which was much improved in texture when baked but didn’t easily allow for a jam layer, which, while still delicious, didn’t really feel like a proper Belgian slice to me.

I tried swirling the jam into the top of the batter, which was delicious, but the moisture from the jam made the icing stay sticky and soft, so it didn’t cut nicely into pieces.

Finally, I tried this version – spreading half of the batter into the pan, adding the jam on top and whacking it into the freezer for a bit to firm up the jam, before spreading the rest of the batter on top.

This makes for the perfect jammy layer in the middle, with a delightfully cakey-yet-slightly-crumbly slice texture. Perfection.

Okay, let’s talk about making this gluten-free Belgian Slice. Here’s what you’ll need:

Ingredients

Butter – You can use salted or unsalted butter.
Brown Sugar
Egg
Gluten-Free Flour – I used my homemade gluten free flour blend here, but you can also use a store-bought gluten free plain flour blend. I have also tested the recipe with Edmond’s gluten free plain flour and it worked perfectly.
Xanthan Gum – This helps stop the slice from crumbling. If you’re using a store-bought flour blend that contains a gum ingredient, you can omit the xanthan gum from the recipe.
Cinnamon & Mixed Spice – If you prefer a less spiced flavour, you can reduce the amount of spice in the recipe. or play around with other spices. But this is the classic combination.
Raspberry Jam – While I’m usually more a fan of less-sugary jams and preserves, this recipe works best with a sweeter commercial jam like Craigs, which tend to be thicker and stickier, meaning they won’t soak into the slice as much.
Icing Sugar
Raspberry Jelly Crystals – These are sprinkled on top for decoration. You can use any kind of pink/red jelly crystals, but raspberry to match the jam is the traditional choice. Most jelly crystals are gluten free, but as always, make sure you check the packet. Greggs jelly is manufactured on equipment that also processes wheat products, so keep that in mind if you’re avoiding traces. Another great option would be to use crushed freeze-dried raspberries instead.

How to Make Gluten Free Belgian Slice

Start by spraying an 8″ (20cm) square cake pan with oil spray (or rub well with butter) and line it with two criss-crossed strips of baking paper.

A large glass jug, with the gluten free flour, cinnamon and mixed spice, having been mixed with a pink-handled whisk.

Sift together the dry ingredients and give them a mix.

The creamed butter and sugar in a large glass bowl, with an egg being added.

Then beat the butter and brown sugar until creamy (2-3 minutes). Add in the eggs one at a time and beat until combined.

Add in the dry ingredients in 2-3 additions. You may want to stir in the last addition by hand, as the batter may be too stiff for the mixer.

Half of the batter spread into a square cake pan, with a layer of raspberry jam being spread on top.

Spread half the batter into the pan. You can eyeball half, or weigh it. Spread the jam over the top of the batter, leaving a 1cm-ish space around the edge. Pop the pan into the freezer for 20-30 minutes or until the jam is firm.

The rest of the batter being spread over the top of the jam layer.

Spoon the remaining batter on top, and gently spread it out evenly. Warming a spatula under hot water will help spread it more easily without disturbing the jam too much.

The baked Belgian slice on a wire cooling rack.

Bake for 35-40 minutes or until slightly golden on top, and a skewer inserted in the middle comes out mostly clean (it’ll probably have a bit of jam on it).

Leave to cool in the pan.

A small glass bowl filled with pink icing, being stirred with a pink-handled whisk.

Once cooled, make the icing by sifting the icing sugar, adding the melted butter and just enough water to make a thick icing. You can add a couple of drops of pink or red food colouring if you like.

The slice, iced with pink icing and sprinkled with pink jelly crystals.

Spread the icing over the slice, and sprinkle the top with jelly crystals. Allow the icing to set before cutting the slice into pieces.

Five randomly arranged pieces of slice on a piece of crinkled baking paper on a old-fashioned metal cooling rack, with a jar of raspberry jam in the background.

Storing the Slice

The Belgian Slice keeps well in an airtight container for 4-5 days. The jam will start to soak into the base, which keeps it moist and makes the flavour even better.

More Gluten Free Slice Recipes

Gluten Free Louise Slice
Gluten Free Weetbix Slice
Gluten Free No Bake Chocolate Slice
Gluten Free Ginger Crunch

Are you new to gluten-free baking?

Or just need some tips on how to make the most of the recipes on GFKF? Check out my start guide to learn how to bake safely and successfully gluten free.

Allergen safety ✔️ Gluten free flour info ✔️
Accurate measuring ✔️ Tools + Equipment ✔️