Mars Bar Cookies

I have a new baking obsession… chocolate bar cookies (aka chopped up classic chocolate bars added to cookie dough and baked to perfection 😍)

So far, I’ve ticked Kinder Cookies and M&M Cookies off my list, and now I’m sharing my brand new chocolate bar recipe Mars Bar Cookies! I love the different flavours and texture that the Mars Bars add to these cookies. The milk chocolate coating melts into the cookie, the caramel is gooey and soft, and the nougat adds a lovely nutty flavour. It’s a 10/10 cookie!

The question is… what chocolate bar cookie should I make next?

Crunchie? Double Decker? Twix?

Comment your favourite at the bottom of this post 👇🏼 Right back to the recipe…

Reasons to love these Mars Bar Cookies

  • Soft and gooey in the middle
  • Chewy and golden on the outside
  • Filled with chopped Mars Bars
  • Flavours of chocolate, caramel and nougat
  • An easy one-bowl recipe
Mars bar cookies

Read these top tips before you start

Mars Bar Cookies are super easy to make, but here are a few tips that will take your cookies from good, to game changer:

  1. Use a mix of brown and white sugar for a soft and chewy texture.
  2. Chill the cookie dough for a deeper flavour.
  3. Roll the cookie dough into balls for thicker cookies.
  4. Leave plenty of space between each cookie so they have enough room to spread out.
  5. Under-bake and leave to cool for a soft and gooey centre.
  6. Push a few extra chunks of Mars Bar into the top of each baked cookie.
Mars bar cookies

How to make Mars Bar Cookies (step-by-step photos & details)

Step 1: Make the cookie dough

You’ll start by making the cookie dough. First melt the butter, then mix in two types of sugar (one white, one light brown), the eggs and vanilla extract. Add the flour and salt, and fold together until the mixture comes together and forms a cookie dough. Now for the best bit, chop up the Mars Bars into bite-sized chunks and fold them into the cookie dough. It should look something like this 👇🏼

Mars bar cookie dough

Step 2: Chill the cookie dough (this is so important)

Chilling the cookie dough develops the flavours and improves the texture. Cold cookie dough = less spread = thicker and softer cookies.

I would recommend making the cookie dough and leaving it overnight in the fridge. In fact, the dough for these Mars Bar Cookies was left for 48 hours. If you’re short on time, chill for at least 4 hours.

Step 3: Roll into balls

First let the cookie dough soften at room temperature for 15 minutes.

Then take one heaped tablespoon of cookie dough and use your hands to roll it into a ball. Place on a lined baking tray and repeat until all your cookie dough is used up. You should get between 10-12 cookies in total.

Leave plenty of space between each cookie so they have enough room to spread out (see image below). I bake mine in batches, with no more than 4 cookies on a large baking tray each time.

Step 4: Bake the cookies

Did you know cookies continue to cook as they cool down? That’s why if you want soft and chewy Mars Bar Cookies, it’s best to under-bake them.

First preheat your oven to 180°C (fan oven). Once the oven reaches the correct temperature, bake the cookies for 10-12 minutes. They’re ready when the outer edge of the cookie is set and golden, but the middle is soft and pale (but not wet).

Whilst the cookies are still warm, use a large round cutter to scoot them into shape (see image below). Leave your Mars Bar Cookies to cool for at least 15 minutes on the baking tray before moving onto a cooling rack.

Recipe troubleshooting

  • Cookies are thin and flat: Did you chill the cookie dough overnight? Did you roll the dough into balls? Make sure you follow these two steps.
  • Cookies are cakey: It’s possible that the dough was overworked or cake flour was used instead of all-purpose self-raising flour.
  • Cookies are hard and crispy: The cookies were over-baked, next time reduce the baking time by 2 minutes .
  • Cookies are burnt and black on the bottom: Avoid using dark nonstick baking sheets, which promote browning and can lead to burning. Instead use a silver/grey baking tray and remember to line with greaseproof paper.

Can I freeze Mars Bar Cookies?

Yes absolutely! Roll the cookie dough into balls, then wrap individually in clingfilm. Store in the freezer for up to 1 month. When you’re craving a cookie, just bake from frozen for 13-14 minutes at 180°C (fan oven).

Equipment & ingredients used for this recipe


Mars Bar Cookies

These delicious Mars Bar Cookies are soft in the middle, chewy on the outside and filled with chopped Mars Bar – caramel, chocolate and nougat, what's not to love!
Prep Time 10 mins
Cook Time 10 mins
Chill time 4 hrs
Total Time 4 hrs 20 mins
Course Dessert
Cuisine Baking
Servings 10

Ingredients
  

  • 150 g Unsalted butter
  • 100 g White caster sugar
  • 150 g Light brown sugar
  • 1 tsp Vanilla extract
  • 1 medium Whole egg at room temperature
  • 1 medium Egg yolk at room temperature
  • 280 g Self-raising flour
  • Pinch of Salt
  • 200 g Mars Bars

Instructions
 

Make the cookie dough

  • Place the unsalted butter in a microwave safe bowl. Microwave for 20-30 seconds until the butter has melted.
  • Add the two sugars, vanilla extract, whole egg and egg yolk into the melted butter and mix together until fully combined.
  • Now fold in the flour and salt. The mixture will come together to form a cookie dough.
  • Chop up the Mars Bars into bite-sized pieces and add them into the cookie dough (save a handful for later) and fold into the cookie dough.
  • Cover the bowl with clingfilm and refrigerate overnight, or for at least 4 hours.

Roll and bake the cookies

  • Preheat the oven to 180°C (fan oven) and line 2 large, flat baking trays with greaseproof paper.
  • Take the cookie dough out of the fridge and leave to soften at room temperature for 15 minutes.
  • Scoop up a heaped tablespoon of cookie dough and use your hands to roll it into a ball. Place on the baking tray and do not flatten. Repeat this step until all the cookie dough has been used up. Remember to leave roughly 8-10cm between each ball so they have enough room to spread out.
  • Bake for 10-12 minutes. The cookies should be golden on the outside but the middle still pale and soft. Don't worry if the middle still looks under-baked, this is how they are meant to be and the cookies will carry on baking as they cool down.
  • As soon as the cookies are out of the oven, push a few leftover Mars Bar chunks into the top of each cookie.
  • Leave on the baking tray for 15 minutes to cool down and firm up. This will change the cookie texture so try to resist the temptation to tuck in straight away.

Notes

Store your Mars Bar Cookies at room temp, in an airtight container, for up to 4 days.
Keyword Eggs, Flour, Light brown sugar, Mars bars, Self-raising flour

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