Grapefruit Poppy Seed Cake

Glazed Grapefruit Poppy Seed Cake

Grapefruit Poppy Seed Cake…can’t you just taste it now? It’s packed to the gills with the essence of fresh grapefruit and positively loaded with poppy seeds.

Glazed Grapefruit Poppy Seed Cake

That’s white grapefruit, by the way, the most under appreciated citrus fruit. Those sugary red and pink varieties are fine, but my heart belongs to the ever so slightly bitter, puckeringly sour white fruit.

Especially when you bake it up in a cake — the flavor is subtle and sophisticated. I’ve used white grapefruit in lots of recipes on the blog, from my unusual GRAPEFRUIT BLOSSOM POT DE CREME, to my HOMEMADE WHITE GRAPEFRUIT VINEGAR. One of the simplest is my GRAPEFRUIT BRÛLÉE which takes the world’s healthiest breakfast ~ a half grapefruit ~ and gives it just a touch of decadence!

Just baked grapefruit poppy seed cake

It’s hard to keep track of all the layers of grapefruit in this poppy seed cake…it starts with fresh juice and zest blended into the batter, then, after baking, the still warm cake gets drenched with yet more juice, and finally the whole thing is topped off with a grapefruit glaze… just in case there were any doubts!

White Grapefruit and Poppy Seed Cake

That extra soaking with fresh grapefruit juice after it comes out of the oven gives this cake more citrus flavor than you could ever pack into it otherwise.

It seems to me that this technique has fallen out of popularity in recent years, we used to do it all the time with lemon and orange pound cakes…stabbing them with chopsticks and filling them to their limit with a thick syrup made by boiling down the fruit juice mixed with  sugar. If you love citrus like I do, it’s one of the few ways to really infuse citrus flavor into anything baked. You could make a grapefruit syrup for this cake, but I think it’s easier, and fresher tasting, to use the plain juice. You can poke holes all over the top to encourage the juice to sink in, or just pour it right down that lovely crack that opens up along the equator of the cake as it bakes.

Grapefruit Poppy Seed Cake batter

I know 3/4 of a cup sounds like an awful lot of poppy seeds, (and it is!) but they give flavor and crunch to the cake, and they create a unique texture as well. You can find inexpensive poppy seeds in bulk containers online at Amazon. But don’t try to do this with the teeny bottles the big name spice companies sell, it’ll put you in the poorhouse! Can you make this with fewer poppy seeds? Sure, it just won’t be as special.

Grapefruit and Poppy Seed Cake

And yes, in case you were wondering, poppy seeds can trigger a false-positive result on a drug test…but no, you can’t get ‘high’ by eating them…so just plan accordingly, and enjoy!

Super moist Grapefruit and Poppy Seed Cake

You are going to need about 2 grapefruits for this cake.

Just baked grapefruit poppy seed cake
4.5 from 8 votes

Grapefruit Poppy Seed Cake

Grapefruit Poppy Seed Cake...can't you just taste it now? It's packed to the gills with the essence of fresh grapefruit and positively loaded with poppy seeds.
Course Dessert
Cuisine American
Prep Time 15 minutes
Cook Time 50 minutes
Yield 16 servings
Author Sue Moran


  • 3/4 cup right poppy seeds
  • 1 cup buttermilk
  • zest of 2 grapefruits
  • 5 Tbsp fresh grapefruit juice
  • 1 cup 2 sticks unsalted butter, at room temperature
  • 1 cup sugar
  • 3 large eggs

dry ingredients

  • 2 3/4 cups all purpose flour
  • 1 tsp baking powder
  • 1 tsp baking soda
  • 1/8 tsp salt

for soaking

  • 1/2 cup fresh grapefruit juice


  • 1 1/2 cups confectioner's sugar
  • several Tbsp of fresh grapefruit juice


  • Set oven to 350F
  • Grease a standard bundt pan.
  • Put the buttermilk in a small bowl and add the poppy seeds, grapefruit juice, and zest. Stir to combine and set aside.
  • Cream the butter and sugar together until fluffy. Beat in the eggs, one at a time.
  • Whisk together the dry ingredients in a separate bowl.
  • Add the dry ingredients to the creamed butter mixture, alternating with the buttermilk mixture. Add about 1/3 of the flour, then 1/3 of the buttermilk, and continue until everything is well combined.
  • Spread the batter in the bundt pan. Smooth the top slightly to make sure it is even.
  • Bake for about 50 minutes, until the top is risen and golden, and a toothpick inserted in the center comes out without wet batter clinging to it.
  • Let the cake cool for about 10 to 15 minutes and then loosen the cake all the way around the pan and invert it onto a plate. If you have trouble removing it, rap the bottom of the pan sharply on a firm surface and try again.
  • Flip the cake back over so the risen side is up. Make little holes with a skewer all over the top and then spoon the fresh juice all over the top, letting the juice seep into the cake. Do this slowly so the juice has a chance to soak in.
  • When the cake is completely cool. pour the glaze over it, and enjoy.
The nutritional information for recipes on this site is provided as a courtesy and although tries to provide accurate nutritional information, these figures are only estimates.

more grapefruit poppy seed love …

Glazed Grapefruit Poppy Seed Muffins from Girl Versus Dough

Grapefruit Poppy Seed Vinaigrette from Cooking Light

Grapefruit Poppy Seed Bread from The Year in Food

Grapefruit Poppy Seed Doughnuts from Baker by Nature

Grapefruit Poppy Seed Bars from Epicurious


Don’t forget to pin this Grapefruit Poppy Seed Cake!

Grapefruit Poppy Seed Cake pin


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    Leave a Reply

    Please rate this recipe!

  • Reply
    Delwyn Wilkinson
    August 21, 2020 at 9:16 pm

    5 stars
    OMG, What an absolute Treat. Super Super delicious…..

  • Reply
    May 3, 2017 at 3:33 pm

    Looks heavenly but I’m wondering why you flip the cake back over so the risen side is up? That is unusual for Bundt cakes.

    • Reply
      May 3, 2017 at 3:37 pm

      I did that because I think the glaze sinks in better, but you can do it either way, Toesin.

  • Reply
    April 7, 2015 at 10:55 am

    5 stars
    I just made this over the weekend and it turned out lovely! It rose really well and was very moist. My glaze didn’t turn out as nice as yours in the photos, but the cake itself was delicious!

    • Reply
      April 7, 2015 at 11:00 am

      Glaze is so tricky, I often need to make it much thicker than I think so that it doesn’t disappear right into the cake!

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