Old-Fashioned Fudge Icing (Vintage Cooked Frosting)

1. Begin beating. Using either a hand mixer or a stand mixer fitted with a whisk attachment, start beating the icing on low speed, gradually increasing to high. This helps incorporate air while encouraging the mixture to thicken and lose its glossy shine.
2. Beat for 5–10 minutes. Continue until the icing becomes creamy, thicker, and noticeably less shiny. You’ll see it start to cling to the beaters and the spatula. The exact time varies slightly depending on humidity, but 5–10 minutes is the target window.
3. Check for readiness. Watch the edges of the bowl closely. When the icing begins stiffening around the sides and looks creamy and dull (rather than glossy), it has reached the perfect consistency. It should pour slowly but spread smoothly.
4. Pour immediately. Spread the icing over your cake or brownies right away, while it’s still warm and workable. It will continue to firm as it cools, creating that classic old-fashioned fudge finish.
5. Add nuts if desired. If you want chopped nuts on top, sprinkle them immediately before the icing sets.

Notes

Because this recipe behaves like candy, small factors — such as humidity, stovetop heat, and cooling time — can affect the final texture. Each batch helps you understand the timing better. Even if it takes a couple of tries, the taste is always delicious, and when you get it just right, the icing gives your cake or brownies a beautiful, nostalgic fudge layer.