You can follow the reduction method here or if you're feeling a little more decadent tonight, a rich roux based sauce.
First thing - get a good Saucier pan (think fry pan with the nice curved sides, no tight corners for anything to hide in). A good pan should be made of stainless steel with a heavy bottom preferably made of aluminum and stainless or copper and stainless. They're sort of a 'sandwich' of the metals, the reason for this is that aluminum and copper are excellent heat conductors, but difficult to clean where stainless steel is easy to clean. You can't make a good sauce with a Teflon pan so don't even bother looking at those.
After you've seared your chicken or other meat in your lovely pan there's those brown caramelized bits that stuck. Those are not for scrubbing away at the sink while you grumble about that silly crimson coat chef who told you to use the damn pan - they're flavour! Called the fond, these are about to become the base for your simple roux based sauce.
Add some oil or butter to your pan if needed, and then throw in some aromatics like minced shallots, onions and or garlic at this point you can add some of your heartier herbs like rosemary. Watch your heat, if you burn that lovely fond now your sauce will also taste burnt and bitter. Now sprinkle in some flour, just plain all purpose flour and make sure every little bit gets coated with the oil in your pan.
Okay I know - How much flour? Here's the rule. Equal parts oil to flour. If it looks like 2 Tbsp of oil, add 2 Tbsp of flour. For planning ahead here 2 Tbsp of roux will thicken 1 cup of liquid.
Stir this mixture constantly, what you want to do for a white roux is just cook out the floury taste. This takes about 2-3 minutes on a medium heat.
There are 3 kinds of roux:
White - cook 2-3 minutes mainly a thickener lending little in flavour except that fond in our case, gives richness
Blond - cook out 4-5 minutes
Brown - for brown sauces like Espagnole or gumbos. Cook out for 20minutes, stirring constantly and for godsake do not stick your finger in a brown roux it sticks and it burns; think napalm. It's also notoriously easy to burn if done over too high a heat and guaranteed to burn if you use butter as your fat.
I'll cover these in more detail in a later post.
Okay back to the pan sauce. Now that you've got this lovely mess of oil, flour and aromatics along with yummy fond bits in the pan add the appropriate amount of liquid; be it milk or stock. Here's another rule for a great roux sauce. Heat your liquid. Then dissolve the hot roux in 25% of the liquid. Add the remaining liquid and
then stir until you get the thickness to your sauce you're looking for.
Season, add some fresh herbs if you like and you have a lovely sauce!
In a nut shell:
Roux = Equal parts fat(oil, butter, duck fat) to flour
2 Tbsp of roux will thicken 1 cup of liquid