Boston Cream Pie | THM: S

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The official dessert of Massachusetts, Boston Cream Pie, is actually a cake, not a pie, and it’s unofficially a favorite type of Tim Horton’s doughnut in this house. Martha Stewart’s Boston Cream Pie recipe is oh-so-good, but unfriendly to the waistline, so I decided to play around with a low-carb version that our whole family can enjoy as a guilt-free treat. I say “treat,” because even though this recipe is a Trim Healthy Mama-friendly S dessert, it’s still quite calorie-dense, so it’s best served on special occasions where a crowd can happily help you enjoy it!

Just like in the traditional recipe, two sponge-y cake layers are stuffed with a vanilla pastry cream, and the top of the Boston Cream Pie is smothered in a smooth chocolate ganache.

The cake layers are made with THM staples you probably have on hand:

The vanilla cream is a mixture of half & half, whipping cream, sweetener, sea salt, egg yolks, vanilla extract, and xanthum gum to thicken it up. (It’s easiest to make this part of the recipe a day ahead of time, since the vanilla cream needs to thicken for several hours in the fridge before use.)

Adding a tablespoon of butter to a ganache made from heavy cream, sweetener, and coarsely chopped 85% Lindt chocolate takes the topping to a whole new level. You’ll see what I mean when you lick the spoon (an essential step).

Yield: 16-20 servings

Boston Cream Pie | THM: S

Boston Cream Pie | THM: S

This low-carb Boston Cream Pie is an incredibly delicious crowd-pleasing THM S dessert! Gluten-free, sugar-free, guilt-free decadence at its finest!

Prep Time 30 minutes
Cook Time 40 minutes
Total Time 1 hour 10 minutes


  • 1/2 cup butter
  • 5 eggs
  • 1 cup sour cream
  • 4 Tbsp xylitol (OR 2 Tbsp Gentle Sweet)
  • 1 tsp vanilla extract
  • 1/2 cup almond flour
  • 1/2 cup coconut flour
  • 1 Tbsp psyllium husk powder
  • 2 tsp baking powder
  • 1 cup half and half
  • 1/2 cup whipping cream
  • 1/2 cup xylitol (OR 1/4 cup Gentle Sweet)
  • pinch of sea salt
  • 4 egg yolks
  • 1 tsp vanilla extract
  • 1 tsp xanthan gum
  • 1/2 cup whipping cream
  • 2 Tbsp xylitol (OR 1 Tbsp Gentle Sweet)
  • 1 3.5oz bar Lindt 85% chocolate, coarsely chopped
  • 1 Tbsp butter


  1. Preheat oven to 350. Line 9" baking pan with parchment paper. Melt butter and let it cool.
  2. Beat eggs for 5-6 minutes until very light and fluffy. Add in cooled butter, sour cream, sweetener, and vanilla extract. Mix thoroughly.
  3. In a separate bowl, stir dry ingredients together. Add to wet ingredients and stir until just combined. Pour batter into the pan and bake at 350 for 35-40 minutes, or until a toothpick comes out clean. Let cake cool completely while you prepare the filling.
  4. To make the vanilla cream, heat half & half and whipping cream together until steaming, but not boiling. In a separate bowl, stir sweetener and salt together. Whisk in egg yolks to make a paste. Slowly pour in hot cream, whisking constantly. Return mixture to the saucepan and bring to a boil. Remove from heat and pour through a strainer back into the bowl. Whisk in vanilla extract and xanthan gum until xanthan gum is completely incorporated. Refrigerate for 4 hours or overnight.
  5. To assemble, slice cake in half horizontally, and spread vanilla cream evenly across the bottom layer (give it a good whisk first). Carefully place on the top layer. Set aside while you make the chocolate ganache.
  6. To make the ganache, heat cream and sweetener in a saucepan until simmering. Pour over the chopped chocolate and stir until smooth. Stir in butter until ganache. Cool slightly before spreading on top of the cake.


Tastes best made a day ahead of time.

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9 thoughts on “Boston Cream Pie | THM: S”

  1. This recipe is hands-down one of the absolute best low-carb desserts I have ever made. My husband is from Boston, and Boston Cream Pie is his favorite, so I made it for his birthday. Everyone loved it… even our teenager! The vanilla cream is so delicious that I even made an extra batch to serve on the side.

  2. Anything I can substitute for the 1/2 cup almond flour? I mostly use Briana Thomas’s baking blend due to tree nut allergies.

  3. Can you tell me what the carb count is for this recipe? Also, what is the psyllium husk used for? Just wondering if I might use whey protein isolate or oat fiber instead? Not a fan on the taste of psyllium husk but don’t want to change the recipe if it’s vital. It looks great, I hope to make it Saturday! Looking forward to hearing from you.

  4. This looks delicious, I have been holding on to the recipe to try for a while! Has anyone had good experience with making it ahead and refrigerating overnight? We are traveling for easter:)


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