Keto Lemon Cupcakes

The fresh flavor of lemons inside a moist cupcake, topped with a creamy frosting that has… you guessed it, more lemon!!

Prep Time10 mins

Cook Time15 mins

Total Time25 mins





For the cupcakes:

  • ▢1 ¾ cups super fine almond flour
  • ▢¼ cup Oat Fiber, see notes
  • ▢2 eggs, divided
  • ▢⅔ cup sour cream
  • ▢½ cup swerve confectioners
  • ▢2 teaspoons baking powder
  • ▢2 teaspoons lemon zest
  • ▢2 tablespoons fresh lemon juice
  • ▢1 teaspoon vanilla extract
  • ▢Pinch of salt

For the frosting:

  • ▢½ cup mascarpone cheese, at room temperature
  • ▢½ cup cream cheese, at room temperature
  • ▢¼ cup  swerve, confectioners (or powdered erythritol)
  • ▢¼ cup heavy cream + 2 tablespoons, or as needed
  • ▢2 teaspoons fresh lemon juice
  • ▢2 teaspoons lemon zest
  • ▢½ teaspoon vanilla extract

US CustomaryMetric


To make the cupcakes:

  • Preheat oven to 350F. Add the flour, baking powder, oat fiber and salt to a bowl and whisk together, then set aside.
  • Separate the eggs, and set yolks aside.  Whip up the egg whites using a hand mixer until you have soft peaks.  Add the swerve to the egg yolks and mix. Then add the vanilla extract, lemon juice/zest and sour cream and continue mixing.
  • Add the dry ingredients into the wet and mix by hand.  Then fold in the egg whites until combined.  Scoop into silicone cupcake liners or paper liners.
  • Bake for 15-18 minutes or until a toothpick, when inserted, comes out clean.  Allow to cool completely before frosting.

To make the frosting:

  • Whip the mascarpone and cream cheese together in a bowl using a hand mixer.  Add ¼ cup of the heavy cream (reserving the 2 tablespoons), swerve confectioners (or powdered erythritol), vanilla extract, lemon juice, and zest, then mix until smooth and creamy.
  • Add more of the heavy cream if needed, to get your desired consistency.  Add the frosting to a piping bag (ziplock bag with the tip cut off will work too), and frost once the cupcakes have cooled completely.
  • Top with fresh grated lemon zest and small slice of lemon.  Store leftovers in the fridge or freezer.


Oat Fiber is made from grinding the outer husks of oats. How healthy is oat fiber? It’s pure insoluble fiber, which doesn’t dissolve in water and isn’t broken down in the digestive tract, so it has zero net carbs and is perfect for a Keto Diet. It helps give a more traditional texture and that’s why I use it so often. Check out all the Keto Oat Fiber Recipes you can make!

To get the best results, it’s best to use oat fiber if you can. If you’re unable to find it, try a combination of psyllium husk powder and coconut flour. Since both are very absorbent, you might have to add more liquid.

Nutrition Facts

Keto Lemon Cupcakes

Amount Per Serving

Calories 273Calories from Fat 234

% Daily Value*

Fat 26g40%

Saturated Fat 10g63%

Carbohydrates 7g2%

Fiber 3g13%

Sugar 2g2%

Protein 8g16%

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