Prep Time: 10 minutes
Chill Time: 30 minutes
Total Time: 40 minutes
Intensity Level: Easy (1 out of 5) – Minimal heat, no baking, simple mixing
Yield: 12 bars
Serving Size: 1 bar
Intensity Breakdown
Task Effort Level Notes
Measuring ingredients Very Low Simple cup measures
Melting butter & marshmallows Low Requires constant stirring
Mixing & pressing Low to Medium Needs light pressure for even layer
Zesting limes Low Optional but recommended
Chilling None Passive time
Overall Intensity: Easy – Perfect for beginner bakers, kids’ kitchen projects, or no-fuss dessert prep.
Why This Recipe Works
Combine the nostalgic, chewy texture of classic rice cereal treats with the bright, tangy, creamy flavor of Key lime pie. These no-bake bars pack a citrus punch, a buttery graham undertone, and a cool, whipped topping finish. They’re ideal for summer parties, bake sales, or whenever you crave a sweet-tart dessert without turning on the oven.
Ingredients
For the Rice Treat Base
6 tablespoons (85g) unsalted butter
10 cups (280g) miniature marshmallows (≈1½ standard 10-oz bags)
1 teaspoon vanilla extract
¼ teaspoon fine sea salt
6 cups (180g) crispy rice cereal (e.g., Rice Krispies)
1 cup (120g) graham cracker crumbs (about 8 full sheets, finely crushed)
For the Key Lime Flavor
⅓ cup Key lime juice (fresh or bottled; if using Persian limes, reduce to ¼ cup + 1 tbsp)
2 tablespoons lime zest (from about 6 Key limes or 3 Persian limes), divided
For the Creamy Topping
1½ cups (180g) powdered sugar, sifted
4 oz (113g) full-fat cream cheese, softened
½ cup (120ml) heavy whipping cream (cold)
½ teaspoon vanilla extract
Pinch of salt
Optional Garnish
2 tablespoons additional graham cracker crumbs
Lime wheels or extra zest
Equipment Needed
Large stockpot (6–8 quart)
Silicone spatula
9×13-inch baking dish
Parchment paper
Stand mixer or hand mixer (for topping)
Microplane or fine zester
Citrus juicer
Instructions
Step 1: Prepare the Pan
Line a 9×13-inch baking dish with parchment paper, leaving overhang on two sides for easy lifting. Lightly spray with nonstick cooking spray. Set aside.
Step 2: Melt the Base (Low Heat, 5 min)
In a large stockpot, melt the butter over low heat. Add the miniature marshmallows and stir constantly with a silicone spatula until completely melted and smooth—about 4 to 5 minutes. Do not overheat (high heat makes treats hard). Remove from heat immediately.
Step 3: Add Flavors (1 min)
Stir in the vanilla extract, salt, 2 tablespoons of Key lime juice, and 1 tablespoon of lime zest. Mix until fully incorporated. The mixture will become slightly looser and pale green.
Step 4: Combine Dry Ingredients (2 min)
Add the crispy rice cereal and graham cracker crumbs all at once. Fold gently until every piece of cereal is coated in the marshmallow-lime mixture. The texture will be sticky and shaggy—that’s correct.
Step 5: Press into Pan (2 min, Light Intensity)
Transfer the mixture to the prepared baking dish. Using a silicone spatula or lightly buttered hands, press firmly into an even layer. Tip: Lay a piece of parchment over the top and press down with a flat-bottomed measuring cup for level bars. Let cool at room temperature for 10 minutes.
Step 6: Make the Key Lime Cream Topping (Medium Intensity for 5 min)
In a stand mixer with the whisk attachment (or using a hand mixer), beat the softened cream cheese alone for 1 minute until fluffy. Add powdered sugar, remaining lime juice (about 2 tablespoons more, total should be ⅓ cup), remaining zest (1 tablespoon), vanilla, and pinch of salt. Beat on low until combined, then scrape down the bowl.
With mixer running on medium, slowly pour in the cold heavy cream. Increase to high speed and whip until stiff peaks form (about 2–3 minutes). Do not overbeat or the cream may break.
Step 7: Assemble & Chill (30 minutes, Passive)
Spread the Key lime whipped topping evenly over the cooled rice treat base. Sprinkle with optional graham cracker crumbs and extra lime zest. Refrigerate uncovered for 30 minutes (or up to 2 hours) until the topping is set and bars slice cleanly.
Step 8: Slice & Serve
Lift the parchment sling out of the pan. Use a sharp knife (run under hot water, then wipe dry between cuts) to slice into 12 bars. Serve chilled.
Storage & Make-Ahead
Refrigerator: Store in an airtight container for up to 4 days.
Freezer: Wrap individual bars in plastic wrap, then foil. Freeze up to 1 month. Thaw in fridge for 20 minutes before serving.
Make ahead: Prepare the rice base a day in advance (keep covered at room temp). Add the topping and chill on serving day.
Nutrition Information (Per Bar)
Approximate values based on 12 servings
Nutrient Amount
Calories 410 kcal
Total Fat 19g
Saturated Fat 11g
Cholesterol 55mg
Sodium 270mg
Total Carbohydrate 57g
Dietary Fiber 1g
Total Sugars 35g
Protein 4g
Vitamin C 6% DV
Calcium 5% DV
Iron 8% DV