Hershey’s Syrup Brownies are a soft, chocolatey sheet-style brownie made with chocolate syrup in the batter and a warm cocoa icing spread over the top while the brownies are still slightly warm. Once everything cools, the icing settles into a fudgy layer that makes these feel more like an old-fashioned frosted brownie than a modern crackly-top brownie.
The ingredient list is a little unusual—four eggs, only one cup of flour, and a full 16 ounces of chocolate syrup—but that is intentional for this formula. I keep the recipe as written and focus instead on not overbaking the thin batter.
These Are Frosted Sheet Brownies, Not Thick Fudge Brownies
The batter is designed for a broad pan, so the brownies bake in a relatively thin layer. That makes the icing-to-brownie ratio part of the recipe rather than an optional decoration.
I would not move this batter into a small square brownie pan without changing the baking time and texture. A 10-by-15-inch pan is the size recorded in the original version on this site.
Ingredients
For the Brownies
- 1/2 cup butter, melted
- 1 cup granulated sugar
- 4 large eggs
- 1 teaspoon vanilla extract
- 1 cup all-purpose flour
- 16 ounces Hershey’s chocolate syrup
- 1 cup chopped nuts, optional
For the Cocoa Icing
- 3 cups confectioners’ sugar
- 1/2 cup butter, melted
- 4 tablespoons unsweetened cocoa powder
- 4 tablespoons milk, divided as needed
- 1 teaspoon vanilla extract
- Extra chopped nuts, optional for the top
The Brownie Step I Watch Most Closely
Do not wait for a bone-dry toothpick. I start checking near the early end of the baking window. A toothpick should come out without liquid batter, but a few moist crumbs are fine.
Mix the flour only until incorporated. Once the eggs and sugar are combined, there is no benefit to aggressively beating the flour into the batter.
Use the syrup as an ingredient, not a topping. The chocolate syrup goes directly into the brownie batter before baking.
How to Make Hershey’s Syrup Brownies
- Preheat the oven to 350°F and grease the bottom of a 10-by-15-inch baking pan.
- In a large bowl, combine the melted butter and granulated sugar.
- Add the eggs one at a time, mixing well after each addition.
- Stir in the vanilla.
- Add the flour and mix just until no dry streaks remain.
- Pour in the chocolate syrup and stir until the batter is evenly chocolate-colored.
- Fold in the chopped nuts if using.
- Spread the batter evenly in the prepared pan.
- Bake for about 35 to 40 minutes, checking toward the early end of the range. A toothpick should come out without wet batter.
- Begin making the icing when the brownies are nearly finished.
- Combine the melted butter, cocoa powder, and about 1 tablespoon of the milk until smooth and warm.
- Place the confectioners’ sugar in a mixing bowl.
- Add the cocoa-butter mixture and vanilla, then beat until combined.
- Add the remaining milk gradually until the icing reaches a thick but spreadable consistency.
- Let the brownies cool for about 5 to 10 minutes.
- Spread the icing over the still-warm brownies.
- Add extra chopped nuts over the top if desired.
- Let the brownies cool completely before cutting so the icing has time to set into its fudge-like layer.
Why I Frost Them While They Are Still Warm
The brownies should not be piping hot, but they should still carry some warmth when the icing goes on. That warmth helps the frosting spread easily across the large pan without needing extra milk.
Then I leave the pan alone until fully cool. Cutting while the icing is still soft makes the top drag across the knife and gives you messy edges.
Nuts or No Nuts?
The nuts are optional. If you use them, you can fold the full cup into the batter or save a small handful for the icing so the top has visible texture.
If serving a group and you are unsure about nut allergies, leaving them out is the simplest choice. The syrup and cocoa icing provide plenty of chocolate flavor on their own.
How to Cut Cleaner Brownie Squares
Wait until the brownies and icing are completely cool. Then wipe the knife between cuts if the frosting begins to collect on the blade.
Because this is a large sheet-style batch, I usually cut smaller squares than I would from an unfrosted brownie. The icing makes each piece richer.
Storage
Store the cooled brownies in a covered container. If stacking them, place parchment or wax paper between layers so the frosting does not stick to the bottoms of the pieces above it.
For more easy chocolate desserts, browse my dessert recipes.
Common Questions
Can I skip the icing?
Yes. The brownies will still bake properly, but the fudgy cocoa icing is a major part of the old-fashioned character of this version.
Why is my icing too thick?
Add milk gradually, a small splash at a time. It is easier to thin a thick icing than to repair one that has become runny.
Why are my brownies dry?
They may have baked too long. Start checking before the full 40 minutes, especially if your pan is dark metal or your oven runs hot.
