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Key Lime Fudge

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Prep Time: 35 minutes     Cook Time: 5 minutes

5 from 29 votes

Key lime fudge is such a special treat. Key limes add a delicious citrusy tang to the fudge. Although key lime pie is perhaps better known, this fudge recipe is well worth making because it’s so good. We are using fresh lime zest and fresh lime juice in this recipe, for the ultimate citrus flavor.

A piece of key lime fudge with a bite taken out of it.
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Key lime fudge makes a great treat after a meal. It also makes a great gift. Wrap some up in cellophane and tie a ribbon around it for an easy yet impressive gift!

Making it isn’t hard at all, especially when you use sweetened condensed milk, which is the key to all fail-proof fudge recipes!

This key lime fudge recipe also uses a homemade crust, and that’s easy to make as well. The crust is baked in the oven while the fudge can be made in the microwave, saving time and effort. One bite and you’ll be hooked on the flavor!

When I'm really in the mood for fudge, I also like to make this dark chocolate fudge or my favorite old fashioned peanut butter fudge.

Main Ingredients

The ingredients to make key lime fudge laid out on a table.

This delicious key lime fudge dessert is simple to prepare, and you will be pleasantly surprised with just how delicious it is! It’s made in two parts so you will make the crust and then the fudge. These bite-sized snacks are more-ish (try to eat just one!) These are the main ingredients:

  • Graham cracker crumbs: To make a crumbly crust.
  • Sweetened condensed milk: Adds a distinctive, rich flavor.
  • Lime zest and juice: Adds a wonderful citrus tang.
  • White chocolate: Adds even more richness.

Instructions Overview

So how do you make key lime fudge? It’s actually pretty straightforward! Make the crust first by combining butter, sugar, and graham crackers. This mixture goes into a square pan and then you bake it in the oven.

While the crust bakes and cools, you can get to work on the fudge itself. You can microwave the sweetened condensed milk with the white chocolate and salt until it melts together. After stirring the lime zest and juice into this mixture, you can pour it over the crust.

You will need to refrigerate the fudge for a minimum of two hours. Overnight is even better. It does take a few hours to completely set. All that’s left to do now is cut it into nine pieces and enjoy!

Three pieces of fudge stacked on each other.

Common Questions

Are key limes healthier than regular limes?

This tasty citrus fruit, which is found in key lime pies, teas, desserts, cakes, and more, is good for your health. Key limes are more acidic than regular ones but they offer similar health benefits. They're rich in Vitamins A, B, C, and D, along with magnesium, calcium and potassium.

Do you cover fudge while it sets?

Fudge must cool slowly because if it cools too fast the sugar content crystallizes and this negatively impacts the texture. In this recipe the fudge sets in the refrigerator, rather than at room temperature like many other fudge recipes. Wrap or cover it to slow down the rate of setting and it will come out gooey and perfect.

Can you turn evaporated milk into condensed milk?

If you have all the ingredients for key lime fudge apart from this one, don't worry because you can turn evaporated milk into condensed milk. Combine a 12-ounce can of evaporated milk with 1½ cups of white sugar in a pan.

Bring it to a boil over a moderate heat, stirring all the time. When the sugar has dissolved and the mixture is a little thick, let it cool then proceed with the recipe. This recipe makes the equivalent of a 14-ounce can of sweetened condensed milk.

What is the best way to cut fudge?

The simplest way to cut up your homemade fudge is to use a thin, long knife to score it in straight(ish!) lines. However, if you want perfect squares, you will need to use a measuring tape and score lines at carefully measured intervals before slicing all the way through.

If you plan to make more fudge recipes, I recommend you make a template on some cardboard to save you having to manually measure each time! Oh, and if the fudge seems to crumble when you cut it, warm the knife blade a bit then try again.

Can I make it ahead?

It needs to be refrigerated for a few hours, so you actually need to make it ahead by at least that much time.

How should I store it?

Keep it in an airtight container at room temperature. Once it has set, it stays that way, so you don’t need to refrigerate it.

How long does it keep?

It will keep for several weeks, but it is so good it will be a surprise if you still have some left after a couple of days!

Can I freeze it?

Wrap each piece in plastic wrap and then put them all in a Ziploc bag or airtight container. Fudge can be kept frozen for up to a year. When you thaw it out, leave it in the plastic wrap. If you remove it first, moisture will condense on top and make it mushy and sticky.

What is the best way to serve it?

Whenever a sweet craving hits, a piece of homemade fudge is always satisfying. It is great served with an after-dinner cup of coffee. Alternatively, you can use it to decorate a homemade cheesecake or cupcakes. You could even stir thin slices into ice cream for an indulgent dessert.

Several slices of key lime fudge laid out on a table.

Chopnotch Tips

  • Key limes, which are also known as West Indian or Mexican limes, are tart and aromatic. If you can get them, use them in this recipe for a great result. If not, you can use regular ones.
  • It might sound strange but humid air can affect the results of this recipe. If you make it in humid or wet conditions, it can absorb moisture from the air and turn out very soft.
  • Use a sharp knife to cut it into squares so the pieces have nice, clean edges. Rinse the blade under hot water in-between cuts to make it even easier!
  • Use milk chocolate if you prefer it to white chocolate. It has a stronger flavor, so use a bit less. You don’t want to overpower the lime flavor.
Key lime fudge squares on a table with limes and a knife.

Fudge has to be one of the most delicious treats ever! Knowing how to make your own key lime fudge means you can rustle up this yummy treat whenever you want.


How to Make

Key Lime Fudge

This fudge is really simple and doesn’t take long at all. It's a sweet treat boasts the tangy flavor of key lime in every delicious bite.
Prep Time: 35 minutes
Cook Time: 5 minutes
Chilling Time: 2 hours
Total Time: 2 hours 40 minutes
Servings: 16 pieces


  • ¼ cup unsalted butter
  • ¼ cup granulated sugar
  • 1 ¼ cup graham cracker crumbs
  • ¼ teaspoon salt
  • 3 ½ cup white chocolate, chopped
  • 14 ounces sweetened condensed milk
  • 2 tablespoons lime zest, finely grated
  • 3 tablespoons lime juice, freshly squeezed
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  • Preheat oven to 375°F and line 9 x 9-inch pan with aluminum foil. Grease the foil with nonstick spray.
  • Melt the butter in the microwave. Once melted, add graham crackers and sugar. Stir them until it forms a texture the resembles wet sand.
  • Now take the prepared pan and scatter the crumbs in the bottom. Press them to even the layer.
  • Bake it for 5 minutes. Remove from the oven and let it cool. Start preparing the fudge.
  • Melt the sweetened condensed milk, white chocolate, and salt in the microwave in 30-second increments while stirring in-between until the mixture is smooth.
  • After that, add the lime zest and lime juice to the white chocolate mixture and stir well.
  • Pour the fudge over the crust and smooth it into an even layer.
  • Refrigerate it for at least 2 hours or overnight.
  • Remove it from the pan. Cut into square pieces with the help of a sharp knife. Run the knife under hot water in-between cuts to make clean squares. Enjoy!
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  • You can use regular limes if you can't get Key limes.
  • Humid air can affect the results of a fudge recipe. Try to pick a day that isn't overly humid or wet.
  • Use a sharp knife to cut the fudge into squares so the pieces have nice, clean edges. Rinse the blade under hot water in-between cuts to make it even easier!
  • Use milk chocolate if you prefer it to white chocolate. It has a stronger flavor, so use a bit less so you don't overpower the lime flavor.

Nutrition Facts

Calories: 536kcal (27%), Carbohydrates: 69g (23%), Protein: 7g (14%), Fat: 27g (42%), Saturated Fat: 16g (100%), Trans Fat: 1g, Cholesterol: 39mg (13%), Sodium: 289mg (13%), Potassium: 340mg (10%), Fiber: 1g (4%), Sugar: 63g (70%), Vitamin A: 294IU (6%), Vitamin C: 3mg (4%), Calcium: 239mg (24%), Iron: 1mg (6%)
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