Help with mixing Egg into butter/sugar for perfect cookies

[ketonoob]

Hi, I'm new to this forum.

I just started using an oven (family has no Oven culture) and I'm a total noob to baking.
I saw a keto cookie recipe that ask to combine soften butter with "sugar" (I use Erythritol), then add in 1 egg at room temperature.
When I add my egg, the mixture always break/split. Clumps/blobs of butter and watery mixture.

I read many articles that it's due to temperature difference of the butter and egg. I live in a warm tropical weather country (Singapore).
Butter is always in the fridge, but egg is always left outside. Many articles talks about the Egg temperature but not the butter.

My butter is nearly 20C (68F) after mixing with my sugar. The egg at room temperature after I break open measures about 33C (91F) so I pre-chill it in the fridge till it drops to about 20C (68F) before I mix in with the butter/sugar mixture.

However, this still creates split/breaks in my mixture. And the mixture's temperature drops even more to 16C (61F) despite both having about 20C (68F) when I start to mix!

Can somebody teach me how do I properly mix them? I'm trying to get this consistency:

Thank You!

 

[PaddyL]

You could try adding about a tablespoon of flour with each egg when you add it to the butter/sugar mixture.

 

[retired baker]

Ignore it, just keep going, add the flour and bake it.
How do they end up ?