Sauce for Fish dishes

I made something seriously unhealthy.
It's so yummy.

You've done it before, I'm sure. You went to the store, said to yourself, "I don't feel like eating what's in my house. I mean, I have food in my house, but that food sucks. I want new food." Maybe you don't phrase things like I do, but I'm a pretty in-the-moment type of person. Right then, it sucks. When I bought it, it was awesome. Golden retrievers and I should hang out.

So we come across some yellow fin tuna filets. Ooo. Fish. Okay, I know that fish are being incredibly over-harvested and I want to not be a part in that, but once in a while one can't help themselves. Maybe the population would go up if everyone only ate seafood once a month, whether they caught it or not. The idea that most of the things we eat from the ocean could die in my lifetime is pretty horrific. We need a change.
I bought the tuna anyway. Maybe I'll die by then, or 2012 is our last year. Maybe there are zombies in Florida and we're already screwed. Who knows? I wanted fish.

To top it off, I wanted this bottle of creamy lemon-dill sauce. Looks gooood. Has a great label and everything.

I can't tell you how much crap was in it. I took chemistry for a year and a half. I can't tell you what the compounds are, but I can tell you that they aren't natural. They were likely created in New Jersey, where a lot of the new flavorings, colors, and additives are often made in factories. I've been trying to get away from the preservative thing, so I chased Kevin down the aisle and away from the nasty (but probably yummy) lemon-dill cream sauce.

I went home, put the pan on with a little olive oil, salt and ground black pepper, and went to making sauce.

Now, I don't know about you guys, but we buy a lot of jars. Have you noticed that? I don't think I like the idea of plastic nearly as much. Why? It's not incredibly reusable. Not in the fashion I'd like, anyway. Sure, I used them as pots, but that's obnoxious. They're flimsy, there's likely going to be chemical run-off, and they blow away sometimes (which is annoying). Upside? It's easy to drill draining holes into them. So it's a give or take (mostly take).
I started keeping my jars from various things (see: pickles, relishes, pesto, bamboo shoots, jams and jellies..) and filled up a whole cabinet. Downside? I'm not really vast with my cabinet space as it is, so this was a huge hit to my kitchen's functionality. Upside? I can jar just about whatever the frick I want, including dressings and sauces. And, believe me, I've made dressings (like olive oil, with some salt and pepper; and Italian herbs such as basil, oregano, marjoram and parsley. Put whatever you want in there and voila, dressing. Oh, and Balsamic  vinegar. That's TONS healthier than store-bought stuff, and TONS cheaper).

I must say that the overall healthiness of the sauce I made today, though, is relatively atrocious. Is it still healthier than in the store? I'm sure. Do I want to eat 3 liters of it? Not really.

I have a jar that looks like it's a little less than a pint; maybe 1.5 cups? So 16-20 ounces. I cut up two sticks of butter, and melted them in the microwave. This is easy. Actually, the whole flipping thing is simpler than pie (why do people say 'easy as pie'? Have you seen some of those pies? The blueberry one I made took about an hour. I guess it was easy but..)
Add about 1/8 of a cup of lemon juice, or to taste. Add about a tablespoon (or more, to taste) of the following things, each: ground black pepper, dill, lemon pepper, coriander. Add about 1/2 tablespoon of brown sugar (work with me, people). 1 teaspoon of white pepper went in there, but I'm not sure how relevant that is.
Then, top off the whole jar with mayonnaise (or, about 3-5 tablespoons; enough to thicken it up.)
Stir the heck out of it with a fork to de-clump the mayo.
It's so good.

It's so unhealthy.
I need to find ways to make this without, you know, 2 sticks of butter and a huge hunk of mayo..I can make my own mayo, and butter, if I wanted, but maybe there're other things, like Greek Yogurt and homemade butter. Or maybe just homemade mayo -- Duke's has a very noticeable flavor in the lemon-dill sauce I just made, and I'm scared it eats up the undertones the coriander is supposed to put forth.
If you make it, but change it, let me know!