Piña Colada Sheet Cake

From scratch (but still easy!), this bakes right up in your trusty 9×13 with a coconut rum frosting and a sweet coconut and cherry garnish.

What You’ll Need

For the Cake

• 2 ½ cups all-purpose flour, 300 grams. Weigh it if you can; if you’re scooping cups, use the scoop-and-sweep so you don’t pack it in.
• 2 teaspoons baking powder
• ½ teaspoon baking soda
• 1 teaspoon salt
• 12 tablespoons unsalted butter, softened
• 1 ¼ cups granulated sugar
• 3 eggs
• 1 (20-ounce) can crushed pineapple in juice. Do not drain; you want every drop of juice in the batter.
• 1 cup shredded sweetened coconut
• 2 teaspoons vanilla extract
• 1 teaspoon coconut extract

Coconut Rum Frosting

• 8 ounces cream cheese, softened. Use full-fat!
• 1 ¼ cups granulated sugar
• 1 ½ cups heavy cream, chilled
• 1 teaspoon vanilla extract
• 1 teaspoon coconut extract
• 2–3 tablespoons rum. (I use Bacardi Gold)
• Maraschino cherries for garnish

Equipment You’ll Need

• 9×13-inch baking dish
• Stand mixer with paddle and whisk attachments. You’re creaming butter, then whipping the frosting to stiff peaks, so a hand mixer can struggle here.
• Fine-mesh sieve. You actually need it to sift the dry ingredients; a colander is too coarse.

Instructions

Prep the pan and sift the dry mix

Heat the oven and grease your 9×13 so you’re not fussing with it once the batter is ready. I like nonstick spray, but you can butter it too.

Sift the dry ingredients

Sift the flour with the baking powder, baking soda, and salt into a bowl.

This will help you get a nice light and fluffy cake.

Cream the butter and sugar, then add the eggs

Beat the softened butter with the sugar until it looks pale and fluffy and doesn’t cling to the bowl in greasy streaks. Watch the color, not the clock, when it’s truly lightened, you’re there.

Add the eggs one at a time, mixing until each disappears before adding the next. If the batter looks a touch curdled, don’t panic; it’ll smooth out once the pineapple and flour go in.

Bring in the pineapple and extracts

Mix in the crushed pineapple with all its juice, plus vanilla and coconut extracts, just until combined. Add all the juice!

If your pineapple has any big, stubborn bits, give them a quick mash with a fork in the can before they hit the bowl.

Fold in the dry ingredients and coconut

Add the sifted dry mix and stir on low until you don’t see streaks of flour. Then switch to a spatula and fold in the shredded coconut. Don’t overmix.

This batter is thicker than a boxed cake but looser than a pound cake thanks to the fruit.

Bake until golden and set

Spread the batter into the prepared pan and smooth the top. Bake on the center rack until the top is golden and a toothpick in the center comes out clean, usually right around the half-hour mark.

If the edges are browning but the middle still looks shiny, tent loosely with foil and give it a few extra minutes. Use your eyes over the timer here; a matte, lightly springy center is the cue.

By the way this is one of the ugliest cakes before it gets frosted! Don’t be alarmed, it will be lovely in the end.

Set the pan on a rack and let the cake cool to room temp. It needs time to settle so the frosting doesn’t melt and slide.

Whip the coconut rum frosting

Beat the cream cheese with the sugar until completely smooth and glossy. Then add a third of the cold cream and mix until lump-free before adding the rest and whipping to stiff peaks.

Whisk in the vanilla, coconut extract, and rum. Start with 2 tablespoons of rum, then taste and see what you think.

Frost and garnish

Pile the frosting onto the cooled cake and nudge it to the edges. I dump it in the center and work outward. The swoops are part of the charm.

Dot the top with maraschino cherries, or add a little snow of shredded coconut if you want the full beachy look. Store in the fridge until you’re ready to serve.

Storage Instructions

This is a fridge cake. Cover tightly in the pan (lid, plastic wrap, or foil) and refrigerate 3 to 5 days. The cream cheese–whipped cream frosting sets up when cold.

Variations

• No-alcohol version: skip the rum in the frosting and add 1 extra teaspoon coconut extract plus 1 tablespoon pineapple juice.
• Toasted-coconut crunch: toast the shredded coconut at 325°F for 6–8 minutes and fold half into the batter, scatter the rest on top of the frosted cake.
• A little lime: add 1–2 teaspoons finely grated lime zest to the batter and 1 teaspoon to the frosting for a piña colada-with-lime vibe.

Questions and Troubleshooting

I don’t have coconut extract. Can I skip it?

Yes. Double the vanilla or add a tiny splash of rum.

Can I leave out the rum?

Yes. Just skip it—no need to replace it. The frosting will still whip up and taste great.

My frosting won’t whip to stiff peaks. What went wrong?

It was probably too warm or under-whipped. Chill the bowl and mixture for 10–15 minutes, then whip again until it thickens.

The center of my cake sank. Why?

Underbaked! Bake. until a toothpick comes out jsut with a few crumbs.

Can I make this as cupcakes or a layer cake?

Yes (about 18–24; bake 18–22 minutes)

Can I use unsweetened coconut?

Yes. The cake will be slightly less sweet and a touch drier—add an extra tablespoon of sugar if you want to match the original.

My cake tastes soapy/coconut-y. Did I overdo the extract?

Yes. Coconut extract is strong! stick to the measured teaspoon. If it’s already baked, balance with more frosting.