(Grain-free!) Blackberry-Lemon Cake

lemon blackberry cake 1

Seeing as we’re coming into the season of leftovers – not just turkey, but mashed potatoes – I thought I had better share this cake already. Had you ever considered transforming your cold mashed potatoes into a cake? If not, next time you make mashed potatoes, it’s worth making extra – if not for those waffles, for a grain-free cake. I kid you not.

Going grain free is kind of the thing right now, but that wasn’t my intention – I came across this on BBC Good Food while looking for a gluten-free birthday cake for a friend this summer, and made it out of sheer curiosity – how does mashed potatoes + ground almonds = cake? But it does – a dense, moist, lemony cake that totally works. And now that it’s not summer anymore, I want to give it a go with fresh cranberries in place of the blackberries.

Look! Totally a cake. No grains.

lemon blackberry cake 4

Not that there’s anything wrong with grains, of course.. but it’s interesting that it works. Kindly ignore the peaches that were in season when I took this. It seems ridiculous to look at a pile of ripe peach slices with an inch of frost on the window behind my head. (Related: 100 year old houses are drafty.)

lemon blackberry cake 2 11.12.24 PM

And perhaps it’s a welcome reprieve from the seasonal onslaught of pumpkin cakes and gingerbread – not that there’s anything wrong with those, either – I just baked a batch of dark fruitcakes myself today. But lemon is totally wintry, although their sunniness comes across as springy and lemonade stands have gone and made them seem summery, when really citrus is at its best in the winter.

As are cranberries. Just sayin’.

lemon blackberry cake 1
lemon blackberry cake 1

(Grain-free!) Blackberry (or Cranberry) Lemon Cake

Recipe link


December 2, 2013

adapted from Good Food Magazine, May 2008

  • Makes: Serves 8.


3/4 cup butter, at room temperature

1 cup sugar

4 large eggs

175 g ground almonds

1 cup mashed potatoes

finely grated zest of 2 lemons

2 tsp. baking powder

1 cup fresh or frozen blackberries, raspberries or cranberries


1Preheat the oven to 350F. Butter a 9-inch round cake pan, and line the bottom with a circle of parchment.

2In a large bowl, beat the butter and sugar until light and fluffy, then beat in the eggs one at a time, beating after each addition. Fold in the almonds, cold mashed potato, lemon zest and baking powder. Gently stir in the berries.

3Spread into the pan, smoothing the top, then bake for 40-45 mins or until golden and springy to the touch.

Makes: Serves 8.

About Julie

14 comments on “(Grain-free!) Blackberry-Lemon Cake

  1. Nicole Boyhouse
    December 3, 2013 at 10:58 am

    Mashed potatoes! Really? That’s so cool. Even though you know I *heart* gluten, I would totally make this because it looks yummy. Also – mashed potatoes? MIND BLOWN.

  2. Agata
    December 3, 2013 at 11:09 am

    Would it be possible to substitute sweet potatoes?

  3. stacey snacks
    December 3, 2013 at 4:55 pm

    I trust you, if you say mashed potatoes, then it’s got to be good.
    I may try this just for the fun of it!

  4. Joanne
    December 3, 2013 at 8:33 pm

    I’m guessing you wouldn’t be putting any garlic or onions in with your spuds…

  5. Heidi M
    December 4, 2013 at 8:38 am

    This is just crazy enough that I’m going to have to try it.
    Any suggestions for a lactose-free substitute for the butter? Maybe applesauce + canola oil? Soy yogurt?

  6. Deb
    December 4, 2013 at 11:09 pm

    I will definitely give this cake a go!!!!!xo

  7. Julie
    December 5, 2013 at 6:51 am

    Agata – I don’t know, honestly. Mashed sweet potatoes tend to be less starchy, so I’m not convinced it would work. If you try it, let us know!

  8. Julie
    December 5, 2013 at 6:53 am

    Joanne – no, definitely no garlicky spuds here! Heidi – I doubt applesauce and oil would work in place of the butter.. both are liquid, so you wouldn’t be able to beat them like you would the butter. I’m thinking this recipe is such a fine balance that such a major swap (it calls for 3/4 cup) would throw it off and it wouldn’t work..

  9. rose
    December 5, 2013 at 9:16 pm

    Will try for my daughter’s friend who can’t eat grains. Looks smashing!

  10. Ginger
    January 4, 2014 at 8:13 pm

    Made this today and it came out great. The kids loved it, so this is a keeper.

  11. Sherene Sieben
    January 25, 2014 at 10:26 pm

    These look amazing and delcious! This will be my next kitchen adventure for sure!

  12. Alice
    February 9, 2014 at 10:41 pm

    This cake is in the oven (looking promising), but the house is filled with smoke, as it ran over onto the oven floor. I should have known the pan looked too full. Should it have been in 2 pans?

  13. Vivian Thier
    September 10, 2015 at 2:34 pm

    Alice, next time put cake pan on a rimmed baking sheet so any overflows are contained…saves cleaning the oven.

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