Grapefruit Blondies

I’ve developed these delicious blondies from my recent Triple Fruit Blondies Everyone loved them, but I felt inspired to use a slightly more unusual fruit. I think these grapefruit blondies are equally lovely, equally tasty, but probably a bit more potent in terms of their ”citrus-ness”.  In fact the two main elements – fudgy white chocolate and tangy grapefruit – are brilliant together.

Makes: 16 medium squares

Level: Quite easy to make; timing it out of the oven can be a challenge

Time: About 90 minutes + cooling time

Equipment: 20cm/8” Square tin, ideally loose bottomed with high sides, a food processor. (I have a Kenwood mini food processor; it’s excellent.)

Fruit pulp ingredients

  • 1 large grapefruit (I used a pink grapefruit, but normal should be OK. Next time I’ll buy two because there’s so much white pith that has to be discarded.)
  • 2 – 3 tsp sugar (granulated or caster)

Blondie main ingredients

  • 225g/8oz butter chopped into small pieces, plus a little for greasing
  • 200g/7oz white chocolate, chopped into small pieces
  • 175g/6oz plain flour
  • ½ tsp baking powder
  • 200g/7oz soft, light brown sugar
  • 100g/3.5oz golden caster sugar
  • 3 large eggs 
  • The grapefruit pulp


1. To make the pulp, cut the grapefruit into small pieces, removing any pips and large pieces of white pith and membrane. Whizz in a food processor with the sugar until it becomes a pulp. You need about 200g/7oz of pulp. Set aside to use later.

2. Grease the tin with a little butter, then line the base and sides with baking parchment.   

3. Melt together the butter and 100g white chocolate either in a bain marie or the microwave, stirring frequently. Leave to cool for 5 – 10 minutes.

4. Heat oven to 180C / 160C fan / 350F / Gas 4. Combine the flour and baking powder in another bowl, with ¼ tsp salt.

5. Place the sugar and eggs in a large bowl. Use an electric hand whisk or stand mixer to beat the mixture until it looks thick and foamy – about 5 – 7 minutes. The egg mixture is ready when it leaves a trail, which sits on the surface for a couple of seconds.

6. Pour the melted chocolate into the whisked eggs and sugar then tip in the citrus pulp. Use a spatula or large metal spoon to gently fold everything together.

7. Sieve the flour mixture into the bowl and fold together again. Stir in the remaining chocolate chunks until well combined.

8. Pour the mixture into the tin. Tap the tin firmly a couple of times on your work surface to settle the mixture.  

9. Bake for 35-45 mins for soft centred blondies. Add on another 5 minutes for a more cake-like texture. Check if the blondies are cooked by giving the tin a gentle shake, they should be mostly set, but a little wobble in the centre is fine.      

10. Cool in the tin. If you want a flat surface to decorate then invert the block when it’s had time to firm up (maybe in the fridge for 30 minutes).

11. To decorate, sprinkle with icing sugar and zest or you could pipe over some white chocolate “zig-zags”. Cut into pieces and place in fridge to firm up some more.