I understand where your coming from. If you are used to cooking “by the seat of your pants” for one scaling to a group is more complex than just increasing the amounts.

A couple things that can trip you up:

Prep: Bigger ingredient amounts mean you probably should prep them before starting. E.g I can peel and dice one potato in the time it takes water to come to a boil. 6 potatoes, not so much. Do a mise en place.

Seasoning: taste more often and consider aiming for a more “average” palette. E.g I like my food with very low salt but more pepper, but I don’t do this when cooking for others.

Pans: larger sizes mean you might have to do some steps in batches (browning) or use two pans where you could have used a single pan for one (e.g. split the pan and brown meat at the same time as cooking onions). Create pans/trays to hold the parts of the meal that are partially cooked. When making a lot of something, a little prep and organization makes things go smoothly since you might be repeating the same task several times, so if that task is a little quicker, you get a big benefit. Whereas you might not want the extra prep pans to wash when cooking for one, when cooking for more the better organization actually makes it go quicker.

You still can cook by taste/eye/instinct for the ingredients and amounts. It’s just that planning and organization becomes more important.

Besides just doubling or quadrupling the recipe? Can’t you make 4x as much and plate 4 portions before digging in?

If you can’t improvise a larger quantity, work off a written recipe until you retrain your sense of portions.

I have found that there are different skills you need to learn if you’re going to make food for 1-2 people vs 4 people or 6+. You’ll find that you can’t simply scale up every recipe you have and that some recipes would require a commercial kitchen to achieve for larger groups. The best you can do is know your kitchen and equipment and its limitations. For example, if I make crab cakes, I need a pan to fry them up in. My pan only fits 4 cakes and you need 2 per person. So what is the solution if I’m cooking for 4 people? You can add another pan if you have one and have another burner open or you can set the oven to a low temp to keep the first batch warm while you cook the second batch. Some items I will cook in the oven instead on the stove if I’m cooking for more people, but then you need to make sure you’re not using the oven for something else. Aside from that, lots of things scale up well. I’m actually living temporarily with my parents and will scale up certain dishes simply by doubling the amount. If I make pesto with chicken, I have a large cast iron pan that I cram 4 chicken breast halves into and then add pasta to a pot in twice the quantity. Then of course there are large scale meals. I’m taking 6+. I usually try to utilize an outdoor grill in this case and make lots of sides ahead of time that can be served cold or warmed up. I hosted Thanksgiving once and I had to make a planner for the meal to make sure I had all the pots and pans I needed at the right time. Don’t know how people do that every year, but it was fun to do once and I learned a lot. I had to cut dishes out because I only had so much oven space or burners or dishes to put them in. In the end, you’ll learn with practice.

I’m approaching this as a “stupid brain won’t do what I want” situation as I used to eat the double portion also. My work around was to cook out of sync to what I ate. This meant I didn’t need to worry about what I was eating “now” because everything I cooked was for later. So as an example, I would cook some chilli, but that day I would be eating some curry that was already sitting in the fridge. If you are wondering how to start the cycle, the simplest solution to avoid your cravings messing it up is to cook and then order takeout somewhere so you don’t eat it any of it.

It could be that the improvising is getting in the way. Does this mean you don’t know what to cook until you do?

find a professional cook book. these books teach you how to calculate recipes and scale them (even in relation to whether something is a side dish or mains, they also include tips on calculating waste/trimmings and what to do with them). check your local library. i think there is a starter course from the culinary institute of America, in German there is “der junge Koch”

1. Do a meal plan for each week, buy groceries based on it for the number of portions.
2. Put out the storage container you’re planning on using before you start cooking, so you remember to fill it while you’re serving yourself.

I’m gonna add another vote to look into some cookbooks. One that comes to mind is called Company by Amy Thielan. It’s specifically about cooking for large groups. Most of the recipes are for large groups though (8-12), so you may end up needing to half the recipes, but the best thing about the book is the prose. She writes a lot about strategies and the planning that goes into cooking for a group. Lots of insights into the ingredients to keep on hand, the equipment to use, and recipes that can be made ahead or are best at room temp to make the whole process less stressful. Getting three hot dishes out at the same time is tough on 4 burners. But a meal with a room temp veggie side, and a cold appetizer, means the attention can be given to the main event. I’m sure there are other books addressing all this, but Amy’s just released and I’ve been cooking from it and loving the shit out of it. I highly recommend it. If you’re hesitant to purchase, maybe check a library to see if they have a copy?