I made a sponge cake using a recipe from an old cookbook and at one point it told me to melt and boil butter and pour the boiling butter into beaten egg-whites, let sit for a minute and then mix gently. This procedure puzzles me. Why should I pour in the butter while hot?

If you want the whole thing, here goes (no measures, 'cause it's in Polish and uses Polish measures, where "one cup" is not what you would call "one cup"):

  • beat egg whites with powdered sugar until stiff
  • pour in melted and boiling butter (or shortening), mix gently after one minute and let sit until it cools.
  • Start mixing again and add egg yolks one by one, then lemon juice and finally flour mixed with baking powder.
  • Mix a bit more.
  • Bake for at least 50 minutes at 160 degrees C

The batter looks fine, it's baking nicely, but the long time is also strange for me, most sponge cakes that I made require just 20-25 minutes of baking. I skimmed the book, but didn't notice any other sponge cake recipe with this approach.

2 Answers 2


As far as I know, pouring hot stuffs into the meringue (beaten egg-white) while mixing will denature the protein, and thus stiffen and stabilize the meringue. However, I have no idea why you should pour and wait, then mix in.

  • Maybe the writer wanted only part of this effect? After all, I was supposed to mix it after a minute, when it was still kind-of-hot and let cool completely before I added anything else. Oct 31, 2012 at 10:35

This is from a low-carb blog, specifically a gluten-free fluff marshmallow frosting recipe with that specific instruction – I asked the writer why she does it that way and here is her response:

There are a few reasons why the hot butter is poured into the beaten egg whites. First of all, the egg whites are beaten first to give the maximum volume to the frosting. Secondly, the butter mixture is poured while it’s hot to prevent gelatin forming lumps or erythritol crystallizing. The hot butter also gives some shine to the frosting when poured into the beaten egg whites.

This is step five on her list of directions; her response is at the very bottom of the page in the comment section.


  • Thank you for your effort, but I was not making a frosting, there was no gellatin at all (or erythritol for that matter, uh, I don't even know what it is and I have a biotechnology MSc), and I can't really imagine a sponge cake with "some shine". What I noticed is that the cake was very dense, not nicely light sponge, but more like a pound cake (I can't find a good translation for "ciasto piaskowe" nor have I eaten a real pound cake, but from what I google it looks similar). Oct 27, 2012 at 8:17
  • @jkadlubowska: Oh! Well, that's very different. Never mind! (channeling Emily Latella). Seriously, sorry; I thought you just wondered the thought process/possible science behind the instruction. Attn: veterans in here: is it proper form to delete what is now clearly a useless answer, or does it stay for documentation purposes? Oct 27, 2012 at 8:26
  • 1
    Don't delete it, it's still very interesting. If I could point one thing about my receipe that is most interesting it would be the fact of mixing hot butter and egg-whites. Your marshmallow link underlines the importance of temperature for gellatin and erythritol, but says little about mixing plain butter (hot) and eggs. It might be about the "shine", but I think it's not important enough in this case. Oct 27, 2012 at 9:15

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