Chocolate Shortbread with Chocolate Buttercream Frosting

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This thick, fudgy Chocolate Shortbread with Chocolate Buttercream Frosting is topped with M&M candy and is every chocolate lover’s dream!

Chocolate lovers, you are going to love me today. It’s not often I share a strictly chocolate recipe. I love chocolate just as much as anyone else, but the way I like chocolate best is when it is paired with something else.  Like peanut butter, caramel, mocha or peppermint.

chocolate shortbread bar with m&m candies

But some days call for good ol’ pure chocolate. This Chocolate Shortbread with Chocolate Buttercream Frosting will come to your chocolate-craving rescue on the longest of days.

What you’ll love about this recipe:

  • easy and quick
  • triple chocolate flavor
  • switch up the recipe to add toppings you love!
  • thick creamy chocolate frosting
ingredients for chocolate shortbread bars

What is shortbread?

Shortbread is a classic, simple recipe of just 3 ingredients: flour, sugar and butter.  

To make a chocolate shortbread, I reduced the flour a bit to our favorite shortbread recipe and added in some cocoa powder.  The result is a thick chocolate layer that slightly resembles fudge. In fact, when we shared these with our Sunday school class, they thought they were fudge.

See below that the batter will be very thick. If you line the pan with parchment paper, then press the batter in and bake, you’ll be able to pull up on the parchment paper to easily remove the bars for clean cuts.

Chocolate Buttercream Frosting

And when you add the chocolate buttercream frosting on top, the fudgy flavor really pops. You already know of my intense love of frosting, so I wanted the frosting layer on these bars to be just as thick as the shortbread layer.  The result?

shortbread bar with a bite out

Perfection.  Just  a warning. These bars are very sweet.  If you’d like them a little less sweet, make a half recipe of the chocolate buttercream. There will still be plenty of sweetness, and maybe you’ll be able to eat two bars instead of just one.

Oh, and have a glass of milk on hand either way. Just because they are more fun with a glass of milk.

Recipe Variations

  • make this shortbread in a round cake pan and cut them in “pie” slices for a change
  • add nuts in addition to or in place of the colorful M&M candies
  • sprinkle the top with pecans and drizzle with caramel
  • Save calories! skip the frosting and press chocolate chips into the top of the unbaked shortbread.
chocolate shortbread bars with chocolate frosting
chocolate shortbread bars with chocolate frosting

Chocolate Shortbread with Chocolate Buttercream Frosting

5 from 2 votes
This thick, fudgy Chocolate Shortbread with Chocolate Buttercream Frosting is topped with M&M candy and is every chocolate lover’s dream!
Servings 12
Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes

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  • 1 1/2 cups plus 2 tablespoons all-purpose flour
  • 1/2 cup cocoa powder
  • 1/2 cup white sugar
  • 1 cup salted butter melted
  • Chocolate Buttercream
  • 1/2 cup mini M&M candies


  • Preheat the oven to 325 degrees.
  • In a medium size bowl, mix together the flour, cocoa powder, sugar and melted butter. Press this mixture into the bottom of an 8×8 square baking pan that has been sprayed with cooking spray. Bake at 325 degrees for 30 minutes.
  • After the shortbread has cooled, spread the chocolate buttercream overtop the shortbread. Sprinkle the M&M's on top.
  • Store in an airtight container.


We like a thick layer of chocolate buttercream on top of our bars. If you’d like these bars to be less sweet, you can make a ½ recipe of buttercream for a thinner frosting layer. Less calories that way too!
The calories shown are based on the bars being cut into 12 pieces, with 1 serving being 1 frosted bar. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information.**


Calories: 425kcal | Carbohydrates: 52g | Protein: 3g | Fat: 24g | Saturated Fat: 13g | Cholesterol: 41mg | Sodium: 211mg | Potassium: 149mg | Fiber: 2g | Sugar: 35g | Vitamin A: 490IU | Calcium: 25mg | Iron: 1.9mg
Course Dessert
Cuisine American
Calories 425
Keyword birthday, chocolate

About Lizzy T

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Fun size wife
8 years ago

5 stars
Chocolate shortbread? My life is complete!

8 years ago

can i use cake flour instead of all-purpose flour?

9 years ago

How long can I keep them in the fridge for till they expire? Can I freeze them?

jillian jarvis
9 years ago

could u please tell me in measurements of how much butter .do you mean 50grams

Amy @ Thoroughly Nourished Life
9 years ago

Oh no! This looks like double the chocolate-y trouble! And the m&ms? There is no substitute 🙂

9 years ago

Wow! This looks so rich and decadent!! Yumm!

Alexandra @ Confessions of a Bright-Eyed Baker
9 years ago

Holy moly this is intense!!! I mean… that super-thick frosting layer! And the chocolate shortbread looks insanely good. 🙂

9 years ago

it looks so fudgey and delicious!

9 years ago

Do you keep it refrigerated or would that make the shortbread too hard?

Deb @ Cooking on the Front Burner
9 years ago

I love chocolate and need we say more! Love this treat and I know John would too!

9 years ago

Oh my, the girls are gonna flip when I show them this recipe! Pinning so we can make it:)

Cindy Eikenberg
9 years ago

Whoa, this looks amazing! Every chocoholic is going to be drooling over this – love! Pinning and sharing – happy Wednesday, ladies!

9 years ago

Oh how I love rich desserts and this looks like it fits the bill well 🙂 I am going to use my gluten free flour on this and see how it comes out. Thanks for the recipe. Pretty pictures too!