Berry Oat Crumble Slice

This easy berry oat crumble slice is packed with hearty ōti (oats), juicy hua (berries) and fresh rēmana (lemon) for the perfect sweet and tangy bake. With its buttery oat crumble topping and jammy berry filling, it’s delicious served warm with melting ice cream, enjoyed with a cuppa, or packed into lunchboxes for an easy homemade treat the whole whānau (family) will love. 🤩

Why you will love this Berry Oat Crumble Slice:

This recipe is simple to make, easy to adapt and perfect for using up frozen or fresh berries. The buttery oat crumble creates the perfect contrast to the soft jammy filling, making every bite sweet, crunchy and comforting. It keeps well for lunchboxes, works beautifully as a dessert, and is the kind of reliable homemade slice recipe you’ll come back to again and again.

More Slice Inspiration:

If you love easy homemade slice recipes, make sure you also try my Louise Cake Slice recipe — a classic favourite that never disappoints. Craving something rich and chewy? The Best Oaty Caramel Slice is packed with golden karamea (caramel) and hearty oats, making it an instant whānau (family) favourite. Or for something nostalgic, try my Peanut Butter Weetbix Slice for a modern twist on a classic bake.

Videography and photography by Sarah Henderson.

Ingredients:

• Berries: Use a a mixed bag of frozen berries for this slice because they hold their shape and taste amazing.
• Sugar: In the video I used huka one (caster sugar) but since developing this recipe I prefer huka hāura (brown sugar). So, choose which one you want to use because both work.
• Lemons: Kiri rēmana (lemon zest) and wai rēmana (lemon juice) are both used in this slice so fresh is best.
• Butter: I prefer salted pata (butter) because of the deep flavour but unsalted works. 
• Eggs: I always use free-range hēki (eggs) but use what you have.
• Coconut: Kokonati (coconut) gives the slice a delicious texture and desiccated or shredded both work.
• Flour: Use plain or high grade flour in this recipe.
• Oats: Use rolled oats for the best overall texture or wholegrain oats that have been chopped in to finer pieces.

HOW TO MAKE THIS YUMMY SLICE:

Note: The full recipe card with the full list of ingredients, instructions and step by step video are found at the bottom of this page.

Tips on how to make the Best Berry Crumble Slice:

Cream the Butter and Sugar Properly:

Take the time to properly cream the pata (butter) and huka (sugar) for the full amount of time listed in the recipe. This helps create a lighter texture and gives the sugar time to fully dissolve into the butter.

Be Gentle with the Berries:

Avoid overmixing or squashing the hua (berries) while they cook. Keeping them as whole as possible helps create a beautiful jammy berry filling with bursts of berry throughout the slice.

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Variations:

Use Different Berries:

This recipe works beautifully with any hua tio (frozen berries). Try rahipere (raspberries), tūrutu (blueberries), parakipere (blackberries), rōpere (strawberries) or a mixed berry blend depending on what you have on hand.

Add Nuts or Seeds:

For extra crunch, stir a handful of chopped wōnati (walnuts), aramona (almonds) or kākano putirā (sunflower seeds) through the crumble mixture before baking.

Make It Extra Lemony:

If you love bright citrus flavours, add extra rēmana (lemon) zest to the crumble or drizzle the cooled slice with a simple lemon icing.

Serve It as a Dessert:

Warm slices served with vanilla ice cream, whipped cream or yoghurt turn this simple bake into an easy crowd-pleasing dessert.

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Storage

Store the Berry Oat Crumble Slice in an airtight container at room temperature for up to 3 days. If your kitchen is warm, it is best stored in the fridge where it will keep for up to 5 days.

This slice also freezes well. Place slices into an airtight container with baking paper between layers and freeze for up to 3 months. Defrost at room temperature before serving.

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Frequently Asked Questions:

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