Thank you, lovely commenters, for giving me the inspiration for writing this post with your questions about how I can cook the way I do and still stick to my diet.
The real answer is: How couldn't I?
The more elaborate answer also goes into both my history with food and cooking and my understanding of what I feel makes a good meal.
My first secret is very simple: Except in the rarest of circumstances, I only eat once a day. One meal, in the evening, is usually all that fits into my schedule, plus I'm just not hungry when I'm busy (which I normally am all the time during the day). 1200-1500 calories is a huge amount to spend on a single meal, so I can go all out. But even if I eat more often than that, I try to keep it to very small portions, or maybe just a small smoothie, because my body just doesn't want food during the day anymore.
The second is...
my spices (stacked three deep, not shown are the fresh ones I keep in my freezer after harvesting) and
salts, peppers, oils and cooking condiments like Mirin (can't fit all of them on that small space so it's mostly different oils) plus spice mixes I'm giving a try (the little packets).
I don't add a lot of extraneous calories to my food- fresh, high-quality ingredients combined the way I feel would be tastiest is my way of cooking. I rarely use recipes- well, I use things I observed from toddlerhood. I've never been a fan of sauces- if I make them, they're usually not cream- but broth-based (made from the cooking juices of whatever I'm preparing).
I'm very privileged in that I have had food security all my life (with the exception of a few end-of-the-month weeks at college/grad school). I also grew up in a coastal town with an abundance of fresh food and with two of the most amazing cooks I know preparing two meals a day (my nonna lives on the same property, my gran isn't that far away). I'm also a very curious person and always have been, so with the exception of a few things I absolutely can't stand, I'll eat anything and everything, which is good if your mom likes to experiment with things like Indonesian hot pepper salad. Not having to pay attention to any food allergies helps, too.
I learned to cook the way a cook might- I started out only being allowed to wash dishes, and vegetables and fruit if I promised to be extra careful. The cooks in the family taught materials science during that time- what everything was, how to prep it, how to use it, what it might go with and what not.
Next, when I was allowed a knife (still before I started school), it was chopping veggies for me (and my brother took over dish-washing duties; my parents were adamant that they learn the same things since my dad regrets to this day that he never learned to cook). More materials science went along with that- how to slice and dice, which ways of cutting released the most flavors in combination with which way of preparing the ingredient, how to be both fast and precise when dicing, why it was important to have evenly-sized pieces of vegetables, what order they were to be added so nothing would get mushy when cooked and so on. There were a lot of hands-on lessons about herbs and spices in there, too- how to pluck them, chop them, grind them, which went together, which didn't, which flavor or scent would be dominant in the resultant dish, how to temper certain rather unwanted flavors- and things like compensating for using a lot of salt e.g. by adding finely chopped celery root or lovage, or that it really hurts if you manage to scrape your fingers along a ginger grater.
A few years later, I think I was eleven, I was allowed to season for the first time. It was a catastrophic failure, despite everything I had learned- I used way too much of everything. Moderation was the key. Around that time my interest in patisserie started, something that was exclusively my own because while the cooks in the family loved to bake, too (and were very good at it), they weren't really interested in the very involved techniques of, e.g., sugar art. I still love experimenting with it, in moderation and miniature.
That's my third secret, by the way- moderation. Now, since I learned cooking by doing so for a very large family with a lot of guests I am incapable of making food for less than four people, but the good thing about that is that my freezer is always full of home-made meals I'll just have to warm up. I tend to cook about once every three days- I have to have dinners out around three nights a week on average, so this rhythm keeps me in food. Moderation for me is preparing things as perfectly as I can, then arrange a reasonable portion of it as beautifully as I can, keeping it at the temperature where the scents waft up to titillate my nose, making my mouth water as I anticipate the flavors and textures that will explode in my mouth upon the first bite.
And thus we have arrived at the fourth secret for me: I'm not punishing my body for forgetting what it means to eat mindfully and intuitively. Most diet food has the appeal, look and taste of cardboard to me. I'd rather not eat anything at all than have it. I love aesthetic food, food that engages the senses and satisfies rather than just satiates. Preparing a good meal, being involved in all stages from shopping to arrangement, just makes tasting, enjoying it so much more satisfactory for me that sticking to my calorie limits and portion sizes isn't hard work. Most of what I make is very simple- just a few ingredients. I try arranging it in a way to please the eye and seasoning it in a way to please the nose, and cooking it so it's not a single mushy texture to please the palate. Food, to me, shouldn't be just fuel, it's a joy. It's sensual, and satisfactory.
I'm attempting to re-learn the way I ate when I still lived at home, before I left for college: Mindfully. Eat when I'm hungry, what I'm hungry for, in a quantity that will still that hunger.
If it's a pastry (like an apple pie, e.g.) I crave, I'll make a batch, then either freeze all but one palm-sized treat or give them away to the neighbors, and enjoy my apple pie. Maybe I'll even make a small amount of vanilla custard to go with it (making it from scratch from low-fat milk doesn't take long and tastes SO good!).
So, to sum it up, my secret to sticking to my plan while also cooking elaborate meals:
-eating once a day
-fresh ingredients, lots of flavors
-mindful eating, portion control and enjoying my food
-food/being on a diet isn't punishment. I'm still living life to the fullest AND enjoying what I eat, just a smaller amount of it.
Some smaller contributing factors: There are no such things as tartar sauce, mayonnaise or ketchup in my home except under very extraordinary circumstances (like a Super Bowl party). I'm not too big a fan of fried foods, and I'm a pescatarian (mostly). I try to make the broths, fonds, and demiglaces I use myself, if not, I buy the ones that consist of all-organic, natural ingredients. Nothing containing MSG or similar flavor enhancers, no bake mixes, the ready-made spice mixes on my shelf all contain nothing but herbs, spices, salts, and vegetables. It's taken me a long time to get my spice collection to where it is- it's a very expensive endeavor to buy everything at once, so go slow. Quite a few things were collected on travels all over the world and might be hard to get, but don't worry: They're never essential.
The final secret: Take your time. Making a great tomato sauce takes me six-eight hours, only one of which is spent actively working. The rest is simmering on very low heat. Anticipation will add even more flavor to your meal. If I have friends coming by (which happens a lot because I have an open house policy- just try if I'm home if you're in the neighborhood and we'll have dinner together), I take even more time eating very slowly while enjoying the company both when preparing the meal and when eating it.
Good food, good company- it's a good life, and I like to savor and enjoy it. There are enough external factors trying to sour it up, I don't need to let them come into those relaxing hours.
Here we come back to my first, short answer to the question: How couldn't I? If I didn't cook, I wouldn't get all the endorphins from the complete meal experience, and being happy? Makes it a lot easier to lose weight for me.