This first one will focus on the dozen "secret ingredients" for great cooking. It's not that these ingredients are so secret, it's that using them is the secret to great quality, and restaurant taste.
1. Butter
Butter is the basic ingredient of... well everything really.2. Cream and/or condensed milk
Almost every decent sauce starts with either plain butter, butter and oilive oil, a roue (butter and flour), beurre blanc (shallots, white wine or lemon juice or white vinegar, sometimes cream, and butter), or beurre noir (shallots, red wine or cider vinegar, and browned butter).
Butter is one of the most basic ingredients in almost all baking. Without butter, most baked goods just don't taste right.
Also almsot all frying, sauteeing, and pan roasting NEEDS butter. To sautee properly I almost always use a mixture of butter and olive oil. This gives a better flavor, and browns the food better.
Finally, butter can be flavored and mixed with almost anything to act as a garnish or topping. It draws and enhances flavors wonderfully (which is why it gets funky in the fridge sometimes.
Honestly, margarine is evil horrible stuff. It's vegetable oil with emulsifiers and proteins added, and then bubbled through with hydrogen until it congeals. I mean who wants to eat that? Oh and baking with margarine is punishible by death (or at least it should be).
You can't have a white sauce without cream; it's that simple. The use of cream in American cooking has fallen on hard times, and that's just wrong. Almost anywhere a recipe asks for milk (except in baking), you'd likely be better of using cream.3. Buttermilk
Heres the thing, milk is welll... watery.
Cream and condensed milk both have far more buttersolids (the things that give dairy it's flavor) than milk. Yes theres more fat in cream, and that adds in texture and flavor, but the non-fat buttersolids are at least as important.
Restaurant cheese sauces? Yeah cream there.
Gravy? HELL yes theres cream there, even in brown gravies. Actually msot brown sauces will have at least a little bit of cream unless it's a clear brown sauce (which will have butter and red wine of vinegar usually).
Oh and white soups? Yeah theres cream in that too.
Seriously, almost anywhere you would use milk in a recipe; a restaurant or pro chef would use half and half, or light cream.
Condensed milk can be used when thickening is important, and where you need a little extra sweetness. I most often use it in baking, or making puddings or dessert toppings.
Then only time I'll use milk in preference to cream (other than in baking which requires precise fat and sugar balances) is when I'm dissolving something in the milk that doesnt like to dissolve in a fatty solution. Even then you can usually get it to dissolve properly by adding a little lemon or lime juice (be careful it can cause curdling).
NEVER EVER EVER cook with skim milk. You might as well just use water, because that's all you're getting with skim. If you are worried about fat content (why are you reading me anyway but...) and your recipe calls for skim, then buttermilk is almost always the better option.4. Sour Cream (unsweetened yoghurt with lemon juice can work as well)
Buttermilk is the left over liquid when butter is made, and as with cream and condensed milk, it contains a lot more buttersolid but almost no fat as compared to whole milk. It WILL have a slightly sour taste, because it has a lot of lactic acid in it, so be careful with recipes that are sensitive to acid.
That said, the most acid sensitive cooking is baking, and buttermilk is just MADE for baking.
Also buttermilk is the basis for a lot of sauces and dressings. It can be made sweet, savory, rich, or tart depending on how you complement it.
Try a buttermilk and sour cream dressing with lime juice, light olive oil (be careful about your fat balance), cracked peppercorns, tabasco, and powdered mustard.
Sour cream is often used as a texturizer, and adds a slight to moderate sharpness to sauces. It's also one of the most basic ingredients to a white dressing. You really can't make eastern european food without sour cream, and a lot of middle eastern food is improved by it (though they would traditionally use yoghurt, which is effectively sour goat cream).5. White Pepper
Funny thing is though? I dont like sour cream. I cook with it, but I dont care for it as a topping.
Don't want to speckle your sauces? White pepper is your friend. Just about every savory sauce needs pepper and salt, but sometimes you dont want the pepper to show (although I LIKE the speckled effect personally, plus I like fresh cracked pepper).6. Balsamic vinegar, hot sauce, and Worcestershire sauce (both vinegar based)
Remember, pepper helps balance out the flavors of fat in your sauces.
Got a brown sauce? A marinade? A Red Sauce? any kind of savory sauce? Use a little balsamic vinegar in it. It adds flavor, and helps emulsify fats. It's especially good in sauces to be used with rare beef.7. Olive Oil
Want the savory flavor but not the sourness of the balsamic vinegar? Toss a little hot sauce or Worcestershire sauce in it (depending on whether you want heat or not) and it WILL be better. Mix it in with your ground beef when making burgers or meatballs. Sprinkle it on your potatos. I put hot sauce in just about everything (I LOVE my alfredo with some hot sauce).
You can't cook italian without olive oil. Hell as far as I'm concerned you can't cook without Olive oil period. Almost every red or brown sauce starts with olive oil.8. Garlic
Olive oil has its own wonderful flavor, AND it absorbs and enhances all the other flavors around it.
Every kitchen should have a strongly flavored extra virgin, and a light salad olive oil
You can't cook without garlic. No really you can't. NOW BE CAREFUL, because most people use WAY too much garlic. Only very rarely should more than one clove of garlic be used in a recipe for four, and most often you should use less. Garlic is such a dominant flavor that you have to be careful about how you use it, and how much of it you use.9. Shallots
WARNING, except as an aid to savory sauces, or on potatos, don't use garlic powder or garlic salt for anything.
If you want restaurant style sauces and sauteed dishes, you will need to use shallots... LOTS of shallots. You clean them, and then mince them so fine they are turned into a paste (pros have a machine that does this for them).10. Cornstarch or Arrowroot (or sometimes potato flakes)
When it's done properly, the shallots will dissolve into any sauce, or into the butter/oil you are sauteeing with.
Personally, I'm not that big a fan of shallots (I'm allergic to onions, and shallots are jsut a mild onion. They dont make me sick, but they give me wicked heartburn), but almost every restaurant sauce uses them.
How do resaurants get their sauces to be so thick and rich and creamy? Well as mentioned above they use butter and cream and buttermilk, BUT that isn't necessarily sufficient for the proper texture, especially in a brown sauce, or any drippings based, or broth/stock based sauce (that's a lot of sauces).11. Parmagian Cheese
Most people try and thicken sauces with all purpose flour. While this CAN work out for you, it isnt necessarily the best way. Flour can very quickly lump up, and glutens can cause problems with the sauce.
So the secret here is to use something else, that will thicken with less material, and that wont clump up. That means corn starch, arrowroot, or potato flakes.
The best gravies start with a drippings and butter flour roue, add some stock, seasonings, and possibly cream, and then the final thickening is done with arrowroot or potato flakes.
Oh and some folks like acorn flour for this purpose, but I've never used it.
Parmagian is the universal cheese. Just about anything you cook that isn't sweet, and needs a little bit of savorieness, or a bit of a crust on it; and parmagian is there for you.12. Cream Cheese
My personal favorite? I mix finely grated parmagian in my breading for chicken picatta.
There is only one thing, too high a heat and the presence of moisture with make parmagian go stringy or grainy unless there is an adequate emulsuffier and acid/fat balance.
Also that stuff in the green tubes? Yeah thats fine for shaking over your spaghettios, but do yourself a favor and go get some REAL parmagiano regiano. You'll thank me.
Cream cheese is another texturizer, and flavoring agent. Plain cream cheese doesnt have a very strong flavor, but it accents other flavors very very well, and it has a wonderful texture and mouth feel. That mouth feel survives melting, which most cheeses can't say.
Cream cheese is also incredibly versatile. It blends equally well with garlic and onions, as it does with strawberrys and honey.
I like to add a little cream cheese into all my cheese sauces, which tends to smoothe them out and richen them up. I also make dessert toppings with cream cheese and sweet flavorings and/or fruit.
Well that's not a lot of info yet, but it's a start. Theres quite a few other "secret ingredients" I can think of, but those are the most important.