Read this recipe all the way through before beginning, get your spices and equipment (skillet, plate, blender, alternate method grinder, and storing container) ready.
In a small, heavy skillet over medium heat, toast the fennel, coriander, and peppercorns.
Watch carefully, because when the fennel turns a light brown you’re going to work quickly: turn on the hood exhaust fan on your stove, then add the red pepper flakes and stir well for 30 seconds.
Turn the mixture onto a plate to cool.
When cool, place mixture in a blender together with the chili powder, salt, and cinnamon; blend until all are evenly ground.
(Alternately, you can use a spice mill/coffee grinder/mortar and pestle to grind the fennel, coriander, peppercorns, and chili flakes, then toss resultant powder with the remaining ingredients).
Transfer the spice rub into a glass jar and store in a cool, dry place; you can also freeze the mixture.
Note: if you prefer a mixture that is less spicy-hot, make sure you use mild California chili powder and/or begin with fewer red pepper flakes, then add to your preference; California chiles in powder are generally less hot and more sweet.
On chicken: sear a chicken in a little olive oil, let cool, pat the rub generously over the bird, then roast it.
Use as dry rub or dry marinade: rub into meat or poultry, refrigerate 4 hours, bring to room temperature, then roast, pan-sear, or grill.
Finishing rub: blend with just enough olive oil to make a paste, then use as a marinade or to finish grilled steaks and seafood.
Other uses: toss with vegetables before pan-roasting, or add to soups and stews.