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Brownie Batter Frosting

Author Izy


  • 2 medium/large eggs , (use pasteurized if you can find them) (see notes)
  • 1/2 cup (110 g) unsalted butter
  • 4 oz (110 g) bittersweet chocolate (I used 70%)
  • 1/2 tsp salt
  • 1 3/4 cups (175 g) powdered sugar
  • 1 tbsp vanilla extract
  • 1/2 cup (65 g) all purpose flour
  • 2 tbsp milk
  • optional: 1/3 cup chocolate chips


  • Crack the eggs into a medium bowl, and whisk together lightly.
  • Using the same saucepan as before, melt the butter and chocolate together.
  • Whilst this mixture is still warm, pour about 4 tbsp of it, 1 tbsp at a time, into the eggs, whisking the eggs constantly. This tempers the eggs :)
  • Add the tempered egg mixture to the butter-chocolate mixture in the saucepan and whisk together.
  • Whisk in the salt and powdered sugar, then return the pan to a medium-low heat and stir constantly with a spatula (making sure to scrape the sides + base of pan) for 5 minutes (this kills any bacteria by partially cooking the batter).
  • Stir in the vanilla extract, flour and milk and whisk until smooth.
  • Pour over the still-warm cake and spread it out evenly, sprinkle on the chocolate chips (if using) and leave to cool to room temperature. To store: cover the pan with plastic wrap and refrigerate.