Pineapple upside-down cake will become old news once you try these amazing citrus upside down muffins! Slices of sweet Mandarin orange become juicy, caramelized, and irresistible. The secret ingredient in this recipe is the addition of citrus-flavored sparkling water to the batter. The carbonated bubbles create a light, fluffy texture that is unparalleled!

Citrus Upside-Down Muffins [Vegan, Gluten-Free]






Cooking Time




  • 2 tablespoons flax meal
  • 1/4 cup plus 1 tablespoon warm water
  • 1/4 cup plus 1 tablespoon melted coconut oil, divided
  • 1 1/4 cups coconut sugar, lightly packed and divided
  • 2 Mandarin oranges, plus zest*
  • 2 1/3 cups oat flour, sifted
  • 1/2 tablespoon baking powder
  • 1/2 teaspoon baking soda
  • 1/2 teaspoon salt
  • 1/2 tablespoon cinnamon
  • 1/2 teaspoon ginger powder
  • 2 teaspoons vanilla extract
  • 1 teaspoon raw apple cider vinegar
  • 3/4 cup citrus-flavored sparkling water (grapefruit is really nice!)


  1. In a small bowl, whisk together the flax meal and warm water. Make sure to add the flax meal into the bowl first, and stir the water into it, as opposed to vice versa. Place the bowl into the refrigerator for 30 minutes so it can gel together.
  2. While the flax egg sits divide 1 tablespoon of melted coconut oil between the 12 cavities of a muffin tin, or 1/4 teaspoon melted oil per cavity. Use your fingers to lightly spread a little bit of oil up the sides of the cavity, but keep the majority of it on the bottom of the cavity, and rub around to evenly coat it.
  3. Divide 1/4 cup of coconut sugar between the cavities (about 1 teaspoon per cavity) sprinkling evenly, just onto the bottom of each cavity.
  4. Zest both of the oranges into a large bowl (you'll use it later) and then peel them. Place the oranges on their side, and slice each into six thin slices. Gently place one slice into the bottom of each muffin cavity. Set aside and preheat your oven to 350°F.
  5. In a medium bowl, stir together the sifted oat flour, baking powder, baking soda, salt, cinnamon and ginger powder until well mixed. Set aside.
  6. Place the remaining 1/4 cup of melted coconut oil and 1 cup of coconut sugar into the large bowl with the orange zest and beat together with an electric hand mixer, just until the coconut sugar is moistened.
  7. Add the vanilla extract, apple cider vinegar and the chilled flax egg into the sugar mixture and beat again until smooth and well mixed.
  8. Pour the sparkling water into the oil and sugar mixture and whisk until smooth. The top will foam from the carbonation, which is normal. Add the dry ingredients into the wet ingredients and whisk until smooth and lump-free.
  9. Divide the mixture between the muffin cavities, filling almost right to the top.
  10. Bake until a toothpick comes out clean, about 18-20 minutes. Let cool for five minutes (not more, not less. You don't want the sugar to start to harden) and then turn the tins upside down onto a cooling rack to release the muffins. Lightly press the muffins down onto the rack to slightly flatten the bottoms and let cool completely.


*Don't use navel oranges, as they aren't as sweet as mandarins. Also, you may want to grab 3 oranges just in case some of your slices are too thick or break. **Room temperature is very important, or the coconut oil will harden when you add the sparkling water. Muffins will become very soft at room temperature so store in an air-tight container in the refrigerator, or freeze.