1. Prep the oranges

    To make the marmalade, halve 1kg Seville oranges and squeeze the juice into a large pan (it can help to do this through a sieve to catch any pips). Scoop out the remaining flesh and pips from the orange halves on to a muslin cloth (along with any pips caught in the sieve) and tie with string to make a bag, then set aside. You should now be left with just the orange peel. Cut into thin strips and add to the pan of orange juice along with the juice of 1 lemon.

  2. Boil the peel

    Add the bag of orange flesh to the pan and pour in 2½ ltr water. Bring to the boil, then simmer for 2 hrs, or until the peel is soft.

  3. Add the sugar

    After the 2 hrs, remove the muslin bag and put in a small bowl. When cool, squeeze out all liquid from the bag back into the pan, along with any juices that have collected in the bowl. Add 1kg golden granulated sugar to the pan and simmer over a very low heat, stirring occasionally, for 15 mins, or until the sugar has dissolved. Meanwhile, put a few saucers in the freezer to use in step 3.

  4. Cook and cool

    Once the sugar has dissolved, bring to a rolling boil for 15 mins, then remove from the heat. Spoon some of the mixture onto a chilled saucer, leave for 1 min, then press. If it is set, the surface will wrinkle under your fingertip. If not, boil for a few more mins and test again. Once set, remove from the heat and cool for 15 mins.

  5. Pour into jars

    Put the marmalade into hot sterilised jars, reserving 150g for the cake. Seal as tightly as possible; leave to cool.

  6. Make the cake

    Preheat the oven to gas 4, 180°C, fan 160°C, and line a 900g loaf tin with nonstick baking paper. Whisk 200g softened unsalted butter and 200g golden granulated sugar together until light and fluffy. Beat in 3 eggs, one at a time, until combined. Fold in 100g wholemeal flour and 100g plain flour, 2 tsp baking powder and 100g of the reserved marmalade, then 3 tbsp fresh orange juice. Spoon into the tin, then bake for 50 mins, covering with foil for the last 15 mins.

  7. Decorate the cake

    Remove the cake from the oven and leave to cool in the tin for 10 mins before transferring to a wire rack to cool completely. To decorate, gently warm the remaining 50g marmalade in a small pan and brush some of it over the cake. Peel (removing as much pith as possible) and thinly slice 1 sweet orange, 1 blood orange and 1 pink grapefruit, removing any pips. Layer up the slices on top of the cake (you may not need them all) then drizzle over any remaining marmalade. Slice and serve with any remaining fruit slices on the side.

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    Calories 314 (16%), sugar 29g (33%), fat 16g (22%), saturates 9g (44%), salt 0.2g (4%), based on 12 servings.

  8. Ingredients

    We've prepared a simple shopping list so you can easily get all you need to make this delicious citrus cake. Be sure to note down the ingredients or take a screenshot before heading to the shops.

    For the marmalade
    1kg Seville oranges, or regular oranges
    1 large lemon, juiced
    2kg golden granulated sugar

    For the cake
    200g unsalted butter
    200g golden granulated sugar
    3 eggs
    100g wholemeal flour
    100g plain flour
    2 tsp baking powder
    150g homemade orange marmalade (from above)
    3 tbsp fresh orange juice
    1 sweet orange
    1 blood orange
    1 pink grapefruit