What’s for dessert – Turning a sponge toffee fail into Sponge Toffee Caramel Fudge Bars

This all started when my husband dared me to make sponge toffee while he was out at his jiu jitsu class. I accepted the challenge, found Chuck Hughes’ sponge toffee recipe online and got to work. Unfortunately, because this was my first time using my candy thermometer, I didn’t have it in soon enough and I let the mixture boil a little too long. Instead of sponge toffee, I got sponge toffee caramel – a lighter texture than regular caramel, but definitely not solid enough to break apart and eat.

No big deal, I thought, I’ll just make a bar instead. I did a half-batch of my favourite, never-fails chocolate cookie recipe and baked it for the amount of time the cookies usually take, then added the sponge toffee caramel to the top and put it back in the oven.

My husband was insistent that this bar needed some marshmallows, so I melted those while the rest was baking. Except that I didn’t bake the cookie base on its own for long enough, and I didn’t let it cool first, so it didn’t set; and then when I put the caramel on top and put it all back into the oven the caramel bubbled and almost burned; and I have no idea what I did wrong when I melted the marshmallow but it would not spread on the top; so instead of getting a beautiful layered bar, I got a mixed up mess.

My first instinct was to throw it all in the garbage and call it a complete fail, but my husband insisted on trying some first. Then he insisted that it was actually really good, so I tried some and what do you know? It wasn’t so bad. I put it in the fridge overnight and the next day, it was fudgey, caramely goodness!

Here’s how to make my Sponge Toffee Caramel Fudge Bars, exactly as I made them. I have a hunch that if you baked the cookie layer for another 10 minutes and let it cool completely, then added the sponge toffee caramel and heated it for maybe 5 minutes or so, you might actually get a proper layered bar. Please let me know if you try it and it works!

Sponge Toffee Caramel Fudge Bars

Not Just Baby Brain's Sponge Toffee Fudge Bar

 Ingredients for sponge toffee caramel:

  •  1 cup sugar
  • 1 cup corn syrup
  • 1 tablespoon vanilla
  • 1 tablespoon baking soda


  1. Combine sugar, syrup, and vanilla in a medium-sized saucepan. Stir over medium heat until sugar is dissolved.
  2. Continue to cook to 300°F (take a spoon and drop a tiny drizzle of the mixture into a bowl of water – if it crystalizes, you’ve reached the hard crack stage which is what you want). Allow to continue to boil for another couple of minutes to create caramel instead of sponge toffee, stirring to make sure it doesn’t burn.
  3. Remove from heat, using a wooden spoon, stir in baking soda quickly (it will become frothy). Pour into an 8 x 8 inch pan, lined with parchment paper and buttered, and let cool completely.

 Ingredients for cookie layer:

  • 1/2 cup butter
  • 1/2 cup brown sugar
  • 1/4 cup + 2 tbsp white sugar
  • 1 egg
  • 1/2 tsp vanilla
  • 1 cup flour
  • 1/4 cup cocoa powder
  • 1/2 tsp baking soda
  • 1/4 tsp salt


  1. Cream butter, brown sugar and white sugar. Add egg and vanilla, mixing well.
  2. Add dry ingredients and mix until combined.
  3. Pour batter into greased 8 x 8 inch pan.
  4. Bake at 375°F for 11 minutes.

Assembling the Sponge Toffee Caramel Fudge Bar:

  1. While cookie base is still hot, put sponge toffee caramel layer on top.
  2. Sprinkle with a bit of sea salt (trust me, you’ll need the salt to counteract all of the sugar).
  3. Decrease oven heat to 350°F and bake for an additional 10 minutes. Keep an eye on the pan to make sure the caramel isn’t burning!
  4. While the bar is cooking, melt about 20 large marshmallows (2 cups?) with a tablespoon of butter in a pot over low heat.
  5. While the bar is cooling, do your best to put a layer of marshmallow over the top.
  6. Let cool and dig in! Very good if you have a piece while it’s still warm, amazing when cooled and refrigerated.

8 Comments on What’s for dessert – Turning a sponge toffee fail into Sponge Toffee Caramel Fudge Bars

  1. Heidi C.
    August 14, 2014 at 8:38 PM (3 years ago)

    What a yummy transformation. Very savvy of you to come up with this out of a mistake.

  2. Krista M
    November 14, 2014 at 2:46 PM (3 years ago)

    Oooh I love the swirly look of these. I want to make these for my kids!

  3. Julie G
    November 18, 2014 at 7:42 PM (3 years ago)

    Great save. It looks yummy!

  4. Darlene W
    November 20, 2014 at 3:24 PM (3 years ago)

    Add some sugar and love and you have a winner

  5. Amy Lovell
    November 27, 2014 at 8:56 AM (3 years ago)

    Looks lovely! I love when one fail becomes a whole new and awesome dish!

  6. Anne Taylor
    August 23, 2015 at 3:09 PM (2 years ago)

    I used to love to make sponge toffee when I was a kid! This looks very yummy in my books!

  7. Carolyn
    February 14, 2017 at 7:36 AM (10 months ago)

    These look delicious!!


Leave a Reply

CommentLuv badge