These grapefruit poppy seed muffins are light and fluffy with a big poppy seed flavor. They have about twice the grapefruit juice and zest of most recipes for a brighter citrus flavor.
If you want even more grapefruit flavor, I provide notes on how much additional juice, zest, and sugar to add to maintain a balance. Since grapefruits are naturally bitter, additional sugar is needed to balance that out.
These muffins are easy to make, mixing all of the ingredient in one bowl without much fuss.
- 1 ⅓ cups white, unbleached flour (6 ounces)
- ¾ cups quick oats
- 1 teaspoon baking powder
- ½ teaspoon baking soda
- ¼ teaspoon salt
- ½ cup sugar
- 2-3 tablespoon poppy seeds see note
- 2 tablespoon grapefruit zest, divided reserve half for sugar topping
- 1 large egg
- ½ cup milk whole preferred
- ½ cup unsweetened applesauce see note
- ¼ cup fresh squeezed grapefruit juice about ½ a medium grapefruit
- 3 tablespoon vegetable oil (melted butter or melted coconut oil work too)
- 3 tablespoon sparkling sugar (for topping) see note
- grapefruit zest
- PREHEAT OVEN to 375℉. Spray muffin tin with cooking spray or use muffin liners.
- MIX DRY INGREDIENTS: In a large bowl, stir together all of the dry ingredients. Remember to only add half of the grapefruit zest (1 tbsp), and reserve the other half for the sugar topping.1 ⅓ cups white, unbleached flour, ¾ cups quick oats, 1 teaspoon baking powder, ½ teaspoon baking soda, ¼ teaspoon salt, ½ cup sugar, 2-3 tablespoon poppy seeds, 2 tablespoon grapefruit zest, divided
- ADD IN WET INGREDIENTS: Add all of the wet ingredients to the large bowl. Stir until combined. Don't over mix or they can become tough.1 large egg, ½ cup milk, ½ cup unsweetened applesauce, ¼ cup fresh squeezed grapefruit juice, 3 tablespoon vegetable oil
- GET READY TO BAKE. Transfer to greased muffin tin. Mix the remaining grapefruit zest with the sparkling sugar in a small bowl. Add about ¾ of a teaspoon to the top of each muffin.3 tablespoon sparkling sugar (for topping), grapefruit zest
- BAKE for about 15 minutes, or until the centers are 200℉ - 205℉. Remove from oven and let cool slightly before removing from the muffin tin.
Adding more grapefruit flavor
These grapefruit muffins have slightly more than a hint of grapefruit flavor. They are noticeably citrus, but don't burst with grapefruit. You need a lot more zest for that, plus added sugar to balance out the bitterness.
Most of the grapefruit flavor will come from the zest, as the flavor in the juice isn't enough to substantially impact the batter. Since the zest is pretty bitter, more bitter than most other citrus, it needs to be used thoughtfully.
One trick to tame the bitterness is with sugar. Sugar reduces our ability to taste bitterness, it's why adding sugar to the top of a raw grapefruit or to a cup of coffee makes them taste better.
With this in mind, we can add more grapefruit zest in two places: the batter and the sugar topping.
- Add 1-2 extra tablespoons of grapefruit zest to the batter along with an extra ¼ - ½ cup of sugar. (This adds 1-2 teaspoons of extra sugar to each muffin, which is 16 to 32 calories, respectively).
- Add 1 extra tablespoon of zest to the sugar topping along with 2 tablespoons of sugar. (This adds ½ a teaspoon of sugar to each muffin which is 8 calories).
There are several varieties to choose from, but if you are looking for the sweetest grapefruit, try Flame and Ruby Red varieties. They are less bitter, which makes them taste much sweeter and require less sugar (especially for fresh eating).
Grapefruit also get sweeter the longer they are left to ripen on the tree. Because of this, grapefruit later in the season (March, April, and even May), often taste better.
When zesting a grapefruit, be careful to avoid the white pith. The pith on grapefruit is extremely bitter. But a fun fact, the pith on oranges is actually barely bitter, making them great for candying.
Don't skip the sugar topping. It adds a lot of grapefruit flavor that otherwise would get lost if it were simply included in the batter. Have you ever noticed how a light sugar topping can make a muffin taste so much sweeter than if the same amount was added to the batter?
This is the same effect we are going for in these muffins. Since the have less sugar in the batter, the topping adds that burst sweetness we're expecting in a muffin. Second, it adds a pop of undiluted grapefruit flavor.
In my opinion, there are 3 levels of poppy seeds you can use.
- Light - 1 tablespoon for a barely noticeable flavor
- Medium - 2 tablespoons, flavor is noticeable but not too forward
- Heavy - 3 tablespoons for a bold poppy seed flavor that you can't ignore (I love it!)
Whatever you use, please smell and taste your poppy seeds first. Since they are a seed with oils, they can go rancid. If your poppy seeds are too old, they can have a bitter flavor.
The good news is poppy seeds last for a long time, often 2-4 years if stored in a cool, dark, dry place. You can also store them in the freezer to ensure their freshness.
If you like cooking with poppy seeds, The Savory Suitcase shares different varieties and uses in the article, "How to use poppy seeds in cooking."
Other ingredient notes
The rest of the ingredients are pretty standard for these grapefruit poppy seed muffins, but in case you are looking for substitutions or simply some clarification, I've includes some notes.
Flour & oatmeal
White flour works best in these muffins. I tried making them with whole wheat flour, and when combined with the oatmeal they turn out a bit gummy. I tried half white flour and half whole wheat and the texture still wasn't great.
For the oatmeal, I used quick cooking oats which seem to blend into the muffins beautifully. You likely wouldn't even know they are in there. If you're looking for that oatmeal texture, however, use steel cut oats instead.
Sweeteners & sparkling sugar
The amount of sugar can be increased without noticeably affecting the texture. I prefer white sugar to brown sugar for the mellow flavor, as brown sugar would start to mask the subtle grapefruit flavor.
For the applesauce, I used an unsweetened snack cup. Those little snack cups you can buy are 4 ounces - a half a cup (or in my case it was 3.9 and it worked just fine).
If you use sweetened applesauce, the muffins will taste great, I assure you. A ½ cup serving of those sweetened little snack cups has about 1 tablespoon of added sugar (a lot for such a tiny cup!). If you want, reduce the white sugar from this recipe by 1 tablespoon.
I buy a lot of products from King Arthur baking, and their sparkling sugar is no exception. You can buy it directly from them for around $13 or from their amazon store but it's almost twice the price. Also check the cake decorating section of your grocery store for other brands. (Both of those are my affiliate links, so I get a small commission if you buy something).
Oil & fat
I made these muffins several times, each with a different fat. They all turned out great and tasted so similar it would be hard to detect what was used.
- Vegetable oil - flavorless
- Olive oil - barely a teeny tiny hint of flavor
- Butter (melted) - maybe slightly richer, but hard to say
- Coconut oil (melted) - couldn't detect the flavor
A healthy snack
Defining the term healthy is relative to each person. My goal is moderation, so I try to swap in whole grains, reduce added sugar, and eat lots of vegetables.
I love a good muffin with a cup of coffee, but bakery style muffins are loaded with so much fat and sugar I limit them to an occasional treat (usually on vacation or when visiting with friends).
These grapefruit muffins are healthy enough to eat more often. They clock in at 170 calories each and are much lower in sugar than most muffins. They have about as much sugar as a container of greek yogurt.
However, if you want your grapefruit poppy seed muffins to be a little more indulgent (perhaps house guests are staying with you), try using the glaze from Girl vs Dough. It hardens to a nice bakery-style presentation thanks to the added butter to give it body.
Or perhaps you are looking for a muffin that is even healthier, you can try the recipe from Pumpkin + Peanut Butter. She does use whole wheat flour and uses maple syrup instead of white sugar. I've made them and can attest that they are tasty, but have a denser, chewier texture common with recipes that use whole wheat flour.
Grapefruit recipes & flavor pairings
If you are looking for creative ways to use up a big bag of grapefruit, or just enjoy eating them this season, check out my guide, "Grapefruit flavor pairings & recipes." It has everything from a grapefruit-honey glazed roast chicken, to blondie bars with a grapefruit frosting.