Poppyseed, Olive Oil, Lemon Sheet Cake

poppyseed lemon sheetcake

The lightest, zingiest sheet cake you’ll ever find and super easy to make. This cake sings with bright, lemon zest, elevated by the fruitiness of extra virgin olive oil. Topped with a fresh, lemon icing, it’s the perfect treat to enjoy with an afternoon cup of tea!


For the Cake
  • 3 t ground psyllium husks (or 3 T ground flax seeds)
  • 9 t water (or 9 T of water if using flax)
  • zest 2 medium, unwaxed lemons
  • 250 ml unsweetened plant milk
  • 1/4 t vanilla
  • 250 ml extra virgin olive oil
  • 320 g caster sugar
  • 350 g plain flour
  • 1.5 t baking powder
  • 1 t salt
  • 2.5 t poppy seeds
For the Glaze
  • 350g icing sugar
  • 60ml lemon juice, from around 1.5 lemons


To Make the Cake

  1. Preheat the oven to 180c. Grease and line a deep baking tray or roasting tin.
  2. In a small bowl whisk together the ground psyllium husks/ground flax seeds with the water. Set aside to thicken into your egg mixture.
  3. In a medium bowl mix together, the lemon zest, plant milk, vanilla, and olive oil. Set aside.
  4. In a large bowl or a food processor, place the caster sugar. Add the plant milk/olive oil mixture and the thickened psyllium husk/flaxseed mixture and blend until the sugar is completely dissolved and the mixture is smooth and glossy. If you don’t have a food processor, use an immersion blender. The blended mixture should be thick and creamy, almost like mayo.
  5. In a separate bowl, sieve and combine the flour, baking powder, and salt.
  6. Add the flour mixture to the milk/sugar/oil mixture in three additions, mixing gently between each addition. Pour the batter into the prepared tin and place in the preheated oven. Bake for 40 minutes.
  7. Once baked, remove from the oven and place the baking tray on a wire cooling rack. Allow the cake to cool completely.

To Make the Glaze

  1. Once the cake is room temperature, sieve the icing sugar into a medium bowl. Squeeze the lemon juice through the sieve to catch any pips. Whisk together well until smooth.
  2. Pour the glaze over the cake and spread to cover the entire surface with the back of a spoon. Sprinkle with poppy seeds and lemon zest (optional) and leave to set for 15 minutes.
  3. Slice into 12 pieces and serve.


This is a super easy cake, but here are a few tips on getting that perfect, light, moist crumb.

Start with the Psyllium Husks/Flax Seeds

These guys will act as your egg replacement and will help hold the whole batter together. Whether you’re using psyllium husks or flax seeds, you’ll need to grind them into a rough powder (you can do this in a blender or spice grinder) and mix them with water to hydrate. Set aside to thicken.

lemon sheet cake icing

Wet Ingredients

Whisk together the lemon zest, plant milk, vanilla, and olive oil. They won’t blend together completely but just make sure you give it a good whisk.

Add the Sugar and “Egg” Mixture

Mix together the sugar and the plant milk mixture. It’s important that you mix until the sugar is well dissolved. Once completely dissolved, add the egg mixture (psyllium or flax) and whisk well until combined. You’ll need to make sure this mixture is super smooth, so check to make sure your psyllium husks haven’t clumped together.

Add the Dry Ingredients and Poppyseeds

Now you have a smooth batter, you need to add in the dry ingredients and the poppy seeds. Try to avoid overmixing the batter at this stage. You’ll activate the gluten and end up with a dense cake.

Bake and Cool

Bake the cake in a rectangular cake tin for 40 minutes until lightly golden on top. Before frosting, make sure you allow the cake to cool completely to room temperature, otherwise, the glaze won’t set.

Glaze the Cake

Whisk together the icing sugar and the lemon juice. The glaze should be quite thick, so don’t be tempted to add more lemon juice. Pour onto the cooled cake and spread out using the back of a spoon.

Slice and Serve

I like to top my glazed cake with some extra poppy seeds and some lemon zest. Once the glaze is set, slice into 12 squares and serve!

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