Ratio for creaming butter with sugar
I have a recipe for upside down pineapple cake by Stephanie Alexander where she called for 175g butter and 150g sugar to cream. I only used 2/3 of the sugar and the cake still comes out soft and moist (although perhaps not as fluffy and lightweight as her recipe). Is there a ratio for creaming butter and sugar? I'm quite concerned with the amount of sugar intake and I don't like oversweet treats and I find my cake a little too sweet for my taste. Could I cut down more sugar
Sugar affects crispness, moisture, and coloration and you have to decide for yourself how little sugar is acceptable. In simple quickbreads and crisp cookies, I usually cut the sugar by half and make up some or all of that with Splenda (packets, NOT the one made for baking). Results don't seem different from full sugar. In these items, I am using melted butter or coconut oil, not creaming the fat and sugar. That might make a difference, or not. You should experiment with the most basic of your recipes. Don't use nuts or chocolate, for example, which would be a waste if you don't like the results and decide to throw away the whole thing.
There is no set ratio, the quantities of butter and sugar depend on the particular recipe - the quantities and nature of the other ingredients, as well as personal taste, would dictate the amount of sugar to be creamed with the butter. Yes, you certainly can cut down on the sugar if you prefer a less sweet product, but there will be a point where the quantity will be inadequate as sugar affects not only taste but browning, texture, etc. Perhaps a good experiment would be to try different quantities to find the sweetness level you prefer where the end result is not compromised. Also, you might consider a compare and contrast with other cake recipes to see what ratios are used, to help determine an optimal quantity for your taste.