I've been making these a lot lately. You gotta have a decent food processor otherwise it would be a PITA. All my measurements are approximations since I rarely measure anything.
The basic things you need are:
Boneless skinless chicken breasts ~1.5 lbs
8oz pkg baby portabella mushrooms
baby carrots ~15 or so
2 tablespoons Worcestershire sauce
1 large egg
1/4-1/2 cup oatmeal
fresh herbs (I like Italian parsley and thyme)
roasted garlic
chopped onion
misc. seasonings, whatever you like ~ garlic powder, pepper, chili powder, cayenne... (probably not salt since Worcestershire is pretty salty)
In food processor, pulse up some oatmeal - set aside & whisk in with fork the egg and worcestshire
then chop up herbs and carrots in FP with some roasted garlic. Remove that and then run the mushrooms through the FP. Set that aside.
Take the chicken breasts and pulse them in the FP until ground up. Then add all the other ingredients and pulse that through. Scrape that into a big bowl and make sure it's all mixed together.
Scoop out with a disher (an ice cream scooper thingy)(to assure uniformity) onto a foil lined & sprayed cookie sheet. Flatten them out to desired burger thickness. Stick in the freezer for at least 1/2 hour (so their easy to put on the grill). Grill (hot) for about ~3-4 min a side. Makes about 18 sliders.
