Frozen banana and peanut butter slice, no added sugar

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Three overripe bananas sitting in the fruit bowl, skins gone past spotty into properly brown, and a jar of peanut butter with just enough left in it to be annoying but not enough to bother decanting. That’s the whole reason this slice exists. I made the first batch out of not wanting to throw anything out, and it’s stayed in rotation ever since because it solves a problem I didn’t know I had: what to serve when it’s thirty-four degrees and nobody in the house wants the oven on.

This is a frozen banana peanut butter slice built on a simple date-and-oat base, no refined sugar anywhere in it, and it sits in the freezer ready to be cut into squares whenever the afternoon gets too warm for anything baked. It’s closer to a healthier take on a chocolate peanut butter bar than a cake, and it doesn’t pretend to be anything fancier than that.

Why this one earns its freezer space

I keep a reasonably small freezer, so anything that lives in there permanently has to justify itself. This slice does, mostly because it uses fruit that’s past its best and turns it into something that tastes deliberately rich rather than like a fruit-saving exercise. The bananas go in essentially liquid once blended, which means no added sugar is doing the sweetening, just ripe fruit and a small amount of honey or maple to round it out. Peanut butter brings the fat and the savoury edge that stops the whole thing tasting like a smoothie in slice form.

What I love about this particular combination is the way the peanut butter firms up properly once frozen, so you get a genuine snap when you bite into it rather than the slightly sad, icy texture you sometimes get from fruit-based frozen desserts. The date base underneath adds chew without needing flour or refined sugar, which puts this in the same naturally-sweetened family as our flourless orange and almond cake, just colder and considerably less effort.

What’s actually in it

The ingredient list is short on purpose. I’ve tried versions with coconut cream folded through and versions with a layer of melted dark chocolate poured over the top, and both are lovely, but the plain version is the one I come back to because it lets the banana and peanut butter do the talking. If you want to dress it up, melted dark chocolate (70 percent or higher) drizzled over the top before it goes into the freezer sets into a thin, satisfying shell. Entirely optional.

A note on the peanut butter: use the natural kind with no added sugar or palm oil, the sort that separates in the jar and needs a stir. The cheaper processed spreads work fine in a pinch, but they’re sweeter already, so you’ll want to go lighter on the honey.

Ingredients

• 200g pitted dried dates, roughly chopped
• 100g rolled oats
• 60g almonds or walnuts, roughly chopped
• 2 tbsp coconut oil, melted
• Pinch of sea salt
• 3 very ripe bananas (about 350g peeled weight)
• 200g natural peanut butter, plus 2 extra tbsp for swirling
• 1 tbsp honey or maple syrup (more if the bananas aren’t very ripe)
• 1 tsp vanilla extract
• Pinch of sea salt flakes, for the top

Method

1. Line a 20cm square tin with baking paper, leaving a bit of overhang on two sides so you can lift the slice out later.
2. Put the dates, oats, nuts, melted coconut oil and a pinch of salt into a food processor. Blitz until it comes together into a sticky, coarse crumb that holds its shape when pressed between two fingers.
3. Press the mixture firmly and evenly into the base of the tin. Use the back of a spoon or the flat bottom of a glass to really compact it, otherwise it’ll crumble when you slice it later. Put the tin in the freezer while you make the topping.
4. Blend the bananas, 200g peanut butter, honey or maple syrup and vanilla until smooth and glossy. Taste it. If the bananas weren’t quite ripe enough, add a touch more sweetener.
5. Pour the banana mixture over the chilled base and smooth it out with a spatula.
6. Warm the extra 2 tbsp of peanut butter for about 10 seconds in the microwave, just enough to loosen it, then drizzle it over the top and drag a skewer or knife through in a few lines to create a marbled effect. Scatter over the sea salt flakes.
7. Freeze for at least 4 hours, ideally overnight, until completely firm.
8. Lift the slice out using the paper overhang, cut into 12 squares with a hot, dry knife, and return any leftovers to the freezer in an airtight container.

Texture is the whole game here

This isn’t a dessert you rush. Straight out of the freezer it’s too hard to cut cleanly and you’ll end up with crumbled edges and a sore wrist. Give it five or six minutes on the bench before you bring the knife down, and dip the blade in hot water between cuts if you want tidy squares for a gathering. Left on the counter too long, though, and the banana layer starts to slump rather than slice, so there’s a window of maybe ten minutes where it’s genuinely at its best. I’ve learned to just cut the whole batch while it’s in that window and put the extras straight back in, rather than trying to cut pieces to order.

The smell when you first open the processor lid with warm dates in it is worth mentioning too, that deep caramel note that has nothing to do with sugar. It’s one of the small pleasures of baking with dates that doesn’t get talked about enough.

A serving idea that earns its keep

I like this best straight from the freezer with a short black, the cold-hot contrast doing most of the work. For something more like dessert, a square alongside a scoop of coconut yoghurt and a few torn mint leaves from the balcony pots turns it into a proper plated finish for a warm-weather dinner. It also holds up surprisingly well wrapped individually in paper and taken on a walk, which is more than I can say for most slices.

Where I’d push back on the health-food version

I’ll be honest about one thing: some of the “healthy” versions of this slice floating around add protein powder, collagen, or extra sweetener on top of the honey, and I think that’s overcomplicating something that’s already well balanced. Bananas and peanut butter together already give you a reasonable mix of carbohydrate, fat and a bit of protein, which lines up with the general guidance on balanced eating patterns from Eat For Health. Stacking extra powders on top doesn’t make it a better dessert, it just makes the ingredient list longer. If you’re trying to make vegetables the default rather than desserts, this slice was never meant to carry that weight anyway. It’s a treat, just a reasonably honest one.

A variation worth trying

Swap the peanut butter for a natural almond or cashew butter if you’ve got someone with a peanut allergy at the table, and use the same quantities. I’ve also made a version with a thin layer of raspberries pressed into the banana mixture before freezing, which cuts through the richness nicely and looks good sliced through. If you’re the type who reads labels closely before buying nut butter in the first place, our guide on how to read a food label without getting lost is worth a look, since added sugar and oil content vary wildly between brands sitting right next to each other on the shelf.

According to the CSIRO’s dietary research, swapping refined-sugar treats for fruit-and-nut-based alternatives is one of the more sustainable small changes people make, mostly because they don’t feel like a sacrifice. That’s really the test I use for anything that goes in this freezer permanently. It has to taste like something I’d choose anyway, not something I’m making myself eat.

Keeps in the freezer for up to six weeks in an airtight container, though in my house it’s never lasted past the second weekend.

– Mei Lin, Golden Door Living kitchen

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