How to Convert My Layer Cake Recipes into Sheet Cakes

In the midst of this crazy pandemic, I have seen so many of you turn to baking to pass the time and escape a little. It’s a really beautiful thing and I’m so inspired by it. I’ve got tons of cake recipes for you to try while you’re homebound, and while I tend to write them for layer cakes, I wanted to show you how to easily convert them into sheet cakes! This way, if you don’t have round cake pans or want to keep things simple with a single layer cake, you can use any of my cake recipes to do it! 

Sheet cakes are very nostalgic for me because they’re what I was raised on. Every year for my childhood birthdays, my mom would bake a single layer cake in a casserole dish, add canned frosting with a butter knife, and top it all with simple birthday candles. It was glorious! 

The sheet cake in this photo looks really similar, but it’s all homemade. I baked my Yellow Cake Recipe in a 9 x 13 casserole dish and frosted it with my Favorite Chocolate Buttercream. You don’t need a ton of cake tools or fancy techniques to make a sheet cake (I frosted this one with a spoon to get those swoops) but if you want to get creative with a non-traditional design, go crazy!

Making the Right Amount of Batter

To bake my layer cake recipes in a 9 x 13 dish or pan, you’ll want to fill it only halfway full. My cake recipes have a bit of rise to them, and filling the pan more full will result in either 1) a really tall single layer of cake or 2) an overflow disaster. Since I know ingredients are semi-scarce right now, I don’t want you to make a big batch of cake batter when you aren’t going to use it all. So here’s a list of my layer cake recipes that you can convert following the instructions below:

For the cakes listed below, you’ll need to half the recipe to make the right amount of batter: 

• Chocolate Peanut Butter Cake
• Milk & Cookies Cake
• Funfetti Cake
• S’mores Cake with Toasted Marshmallow Buttercream
• Milk & Cereal Cake
• Churro Cake 
• Lemon Cake with Cream Cheese Frosting
• Strawberry Lemonade Cake
• Coffee Cake with Vanilla-Espresso Buttercream
• Favorite Matcha Cake 
• Salted Caramel Apple Cake
• Almond Joy Cake (Coconut Almond Cake)

The cakes listed below can be made as-is, but fill the 9 x 13 pan no more than half full. OR, if you really want to do the math, you can ⅓ the cake portion of the recipe to make just the right amount: 

• Perfect Vanilla Cake 
• One-Bowl Chocolate Cake
• Yellow Cake 
• Chocolate Oreo Cake 
• Thin Mint Chocolate Cake
• Pretzel Nutella Cake
• Ruby Chocolate Cake
• Spiced Vanilla Chai Cake
• Pumpkin Cake 

Preparing the Sheet Cake Pan 

Once you’ve found the perfect recipe, you’ll need to prepare the pan you’re using for best results. You can use a 9 x 13 inch glass or ceramic casserole dish, or a metal pan of the same dimensions. I tend to use glass or ceramic dishes (especially love this one that came as part of a set from Crate & Barrel) just because I love the way they look right out of the oven, but you can use whatever you have on hand.

Either way, prepare the pan or dish by spraying the sides and bottom generously with cooking spray (I love Baker’s Joy for this). You can alternatively grease the pan generously with vegetable oil, or just grease the sides and place a piece of parchment paper on the bottom.

Baking the Sheet Cake 

Once you’ve filled your prepared pan or dish with cake batter (remember, no more than ½ full!) bake it at the oven temperature the recipe instructs. For my cake recipes, I always bake at 350ºF. Add 5 minutes to the baking time in the original recipe and check for doneness then by inserting a toothpick into the center of the cake. It’s done when the toothpick comes out clean.

If it seems to need more time, add an additional 3-5 minutes to the baking time and check again. 

Frosting and Decorating the Sheet Cake 

You can use any of my frosting recipes to decorate your sheet cake, and if the cake recipe you chose calls for a specific buttercream recipe, be sure to half that portion of the recipe to make just enough for your sheet cake. To create the look pictured, use a spoon or butter knife to swirl the frosting around on top of the cake, then add some sprinkles to tie it all together. Totally quick and failproof!

If you’d rather get more elaborate with your sheet cake decorating, feel free to use piping tips and creative cake decorating techniques to create what you’re imagining! This floral sheet cake tutorial shows how to create one of my favorite sheet cake looks: 

Make Ahead and Storage Tips

You can bake the sheet cake ahead of time and store it in its dish at room temperature, covered tightly with plastic wrap, a day or two ahead of frosting. Once it’s frosted, the buttercream will preserve the cake underneath and keep it moist. I still recommend covering it with plastic wrap while you’re storing it (especially after cutting into it) because the extra protection helps keep it fresh for 3-4 days. 

You can keep your cake in the refrigerator as an alternative to room temperature, but I only recommend that if your kitchen environment is warmer than 70ºF. If you do refrigerate your cake, be sure to bring it back to room temperature before serving it because cake tastes best at room temp!

I’m so excited to provide you with lots of fun cake recipes for you to try as sheet cakes! Let me know which ones you try in the comments section, and be sure to tag @sugarandsparrowco on Instagram to show me how you decorated. I love to see what you’re caking. Stay safe and healthy out there, everyone!