Key Lime Fudge

Featured in: Indulge in Heavenly Sweet Treats

Once milk, sugar, and salt come to a boil, dump in marshmallows, white chocolate, juice, and lime shreds. Stir until silky and melted, pour out, let cool, then slice up for a tangy white fudge treat.

Lily chef cooking Cookingwithmee blog.
Updated on Fri, 06 Jun 2025 13:52:22 GMT
Creamy fudge squares bursting with lime, next to halved fresh limes and lots of zest sprinkled everywhere. Pin it
Creamy fudge squares bursting with lime, next to halved fresh limes and lots of zest sprinkled everywhere. | cookingwithmee.com

This sweet treat gives classic summer pie a run for its money! Smooth lime flavor mixed with plenty of creamy goodness it's pretty much happiness in a bite. My friends can't stop munching on it at get-togethers. Seriously, you'll wish you'd made a double batch!

Why You'll Flip For This

Tangy lime and silky white chocolate come together for a wild flavor combo. It's kind of like if fudge and pie teamed up! Making it doesn't take much effort at all. My little guys love squeezing out the limes, and everyone tries to get the last bit from the bowl.

Stuff You Gotta Grab

  • Citrus: 1/4 cup key lime juice, squeezed fresh
  • Sweet Kick: 2 cups granulated sugar
  • Kick of Salt: 1/4 teaspoon plain salt
  • From The Pantry: 2/3 cup evaporated milk (not the kind with sugar!)
  • Pillowy Marshmallows: 2 cups mini marshmallows
  • Zesty Extras: 2 teaspoons lime zest
  • Creamy Chips: 1 1/2 cups white chocolate chips

Irresistible Crowd-Pleaser Fudge

Ready Your Gear
Lay parchment paper in your pan trust me, it makes pulling the fudge out super simple!
Mix It Up
Toss milk, sugar, and salt in your pot. Let it heat up and keep stirring until it bubbles. Don't stop stirring for about 8 more minutes. Feels long, but totally pays off!
Add Everything In
Take off the stove and drop in marshmallows, chocolate chips, lime juice, and all that delicious zest. Stir till it's all one smooth, shiny mix.
Let It Set
Tip it into the lined pan and smooth out the top. Set it on the counter to cool and toss it in the fridge so it gets nice and solid.
Slice and Enjoy
Cut into pieces and serve! Store what’s left in the fridge—good luck having leftovers though!

Switch Things Up

No luck finding key limes? Regular limes are just fine. Sometimes I make it look cute with a tiny drop of green coloring, and crushed graham cracker on top is a game-changer for that pie vibe.

Little Tricks I Love

Lime zest is the real MVP don't skip out! Keep stirring your mixture so it doesn't turn clumpy. In a hurry? That Nellie & Joe's key lime juice will totally do the trick!

How To Keep It Good

Stick it in an airtight box in the fridge it stays awesome for weeks. Want to freeze some? Just bundle it up with parchment so the squares don't stick together!

Fun Ways To Change It

Crumbled graham cracker over the top brings big pie energy. Feel like coconut? Toss some in too! Drizzle some melted white chocolate if you wanna get all fancy.

Must-Have Tools

You'll want a sturdy pot, trusty spatula, maybe a thermometer if you have one handy. An 8x8 pan and parchment paper make things so much easier too!

Unbeatable Party Treat

This fudge is always the star at any time from hot summer days to winter feasts. I like packing up extras for gifts that sweet-tart flavor just wins people over every time!

Lots of limey fudge chunks stacked on paper, with a few halved limes close by. Pin it
Lots of limey fudge chunks stacked on paper, with a few halved limes close by. | cookingwithmee.com

Frequently Asked Questions

→ Can I use regular limes instead of key limes?

Yep, regular limes work too. You might want to use a little less juice since they're usually not as sharp as key limes.

→ Why use marshmallows in fudge?

Marshmallows keep the fudge super creamy and hold it together. Plus, they make it way less likely to get gritty sugar bits.

→ Why line the pan with foil?

Foil makes pulling the fudge out of the pan a snap. Just remember to grease it so the fudge comes out easily and cuts look nice.

→ Do I really need to stir constantly?

You do! Stirring all the time stops it from burning and keeps the fudge velvety. Don’t stop now—this is what makes it perfect.

→ How do I know it's ready without a thermometer?

Let it bubble for around 5 or 6 minutes until it thickens and gets just a bit darker. As long as your heat stays steady, just watch the time and you'll be fine.

Key Lime Fudge

White chocolate packed with zesty lime and fresh juice. Tastes sweet and punchy at once. Enjoy every creamy little square.

Prep Time
15 Minutes
Cook Time
8 Minutes
Total Time
23 Minutes
By: Lily

Category: Decadent Desserts

Difficulty: Intermediate

Cuisine: American

Yield: 36 Servings (36 squares)

Dietary: Vegetarian, Gluten-Free

Ingredients

01 Grated zest from 5 limes—about 1/4 cup.
02 5-ounce can of low-fat evaporated milk.
03 1/2 tsp salt.
04 1 2/3 cup white sugar.
05 2 tablespoons of key lime juice from 5-7 limes.
06 2 cups of white chocolate chips.
07 12 big marshmallows, cut into quarters.

Instructions

Step 01

Grease a piece of foil and line your 8x8 pan with it.

Step 02

Heat sugar, salt, and evaporated milk in a solid saucepan over medium. Let it bubble.

Step 03

Turn down the heat a bit and keep stirring for 5–6 minutes as it boils.

Step 04

Off the heat, mix in marshmallows, lime zest, lime juice, and chocolate until smooth and creamy.

Step 05

Evenly pour mixture into the pan and let it fully set and cool.

Step 06

Slice into little 1-inch pieces.

Notes

  1. Feel free to swap key limes with regular ones.
  2. 8-inch pans work nicer than 9-inch ones.
  3. A double boiler isn’t needed but makes things simpler.

Tools You'll Need

  • Solid saucepan or optional double boiler.
  • 8-inch square baking pan.

Allergy Information

Please check ingredients for potential allergens and consult a health professional if in doubt.
  • Contains dairy.

Nutrition Facts (Per Serving)

It is important to consider this information as approximate and not to use it as definitive health advice.
  • Calories: 100
  • Total Fat: 3 g
  • Total Carbohydrate: 17 g
  • Protein: ~