Make a buttery sauce less oily

You want emulsification.

Emulsification is the breaking up a fat and dispersing it into a liquid (or vice versa, dispersing a liquid in a fat). A classic example of an emulsification, also known as an emulsion, is mayonnaise.

There are at least two good ways you can emulsify your brown butter, soy sauce, and lemon juice. One way is called shearing, which is just what it sounds like. You're basically cutting off slices of droplets, making them smaller and smaller. The smaller the microdroplets, the more stable the emulsion. You can accomplish a short-lived but great textured emulsion with just energetic whisking of your liquid and fat ingredients. You can make the micro-droplets even smaller and your emulsion more stable by using a blender or immersion blender.

A second thing you can do to bind your liquid and fat ingredients into a much firmer and more stable emulsion is to add an emulsifier, an egg yolk being a very solid candidate for the job. Energetically whisk in about half of an egg yolk while slowly bringing the cool sauce to just above perfect serving temperature. If you like where the sauce is going, and would like it to be even more like that, temper, then add the other half of the yolk. Mustard is pretty effective too, for a different flavor.

If this sauce is your own creative invention** and you make it a little different each time, it sounds like you aren't averse to experimentation... So my suggestion would be to try substituting a little bit of cream (fairly heavy cream, like whipping cream) for some of the butter. Yes, cream is also just full of butterfat, but the homogenized nature of it can help emulsify the fat with the other components of the sauce. Of course it will be just as fatty and rich, but I think it might not feel quite so greasy on your tongue.

Another idea would be to stir in a little cornstarch slurry - at the very end of cooking: You know, a little bit of milk mixed thoroughly with a teensy bit of cornstarch. Like maybe a couple tablespoons milk and maybe a half teaspoon cornstarch. Stir those two together good so no starch is left unmixed, then stir that cloudy-milky mixture quickly into the sauce while it is still cooking. This will thicken slightly to counteract the dilution of the milk, and the whole thing should make a nice emulsion with the butterfat, masking the greasiness.

**PS it sounds delicious

I would try adding an additional tsp of lemon juice. acids are often used to cut that fatty film left on your palate from rich foods. Other than that I'm not sure...you mentioned not wanting to dilute the flavor by adding more pasta, so I'm sure you would not like any result found by leaving out the butter.

If you wanted to try something with a little different taste, you can half the butter and use either a chicken stock or vegetable stock to replace some of the ommitted butter. But it won't be the same.

I agree with Jolene.. above. It sounds like the easiest way to fix your problem would be to cut a little bit of cream into your sauce. Maybe use half the amount of butter and add a little cream? What’s happening is the butter is breaking under high heat and therefore separating. Cream would do the same thing but you would have to actually reduce it quite a bit. Because it is much more stable than butter under that type of heat give it a shot. Make sure and reduce it a little for thicker body if you want/need. We used to do this sauce similar to what you’re talking about it was a shiitake soy cream ( but we also cut a little brown sugar in there so it was like a teriyaki cream LOL ) really good!!

• as a general rule if you’re getting something that you’re experiencing it is because you’re sauce is “breaking “ it has either gotten too hot or too far reduced to the point where the fats and solids will no longer stay together. Another way to fix this is to quickly whisk in some cold cream or even an ice cube once you see the sauce beginning to break ( separate )