My family has been making these for years, the recipe is from an old Iroquois County (IL) Extension Agency cookbook.

Ingredients

1. 1 dozen eggs
2. 2 lb brown sugar
3. 4 cups sugar
4. 1 Tbsp vanilla
5. 1 Tbsp Karo syrup
6. 1 lb butter (softened at room temperature)
7. 3 lb peanut butter
8. 18 cups oatmeal
9. 1 lb chocolate chips
10. 1 lb M&Ms

In a large bowl, combine ingredients, in order, fully incoporating each before adding the next. After you are done mixing, preheat your oven to 350 degrees F. This allows the batter some time to “rest” before cooking. Bake for 12 minutes.

To allow for more even cooking, you should preheat your cookie sheets in the oven before using them and use a measured scoop for dipping out the batter. I believe we use a #40 similar to this one.

Update: Mom made another batch, the yield is around 200 cookies.
Update(4/17/05): Our copy of the recipe was missing the white sugar, corrected. Working on another batch now.
Update (06/29/05): Thanks to a friend who actually cared about the caloric content, here is the estimated nutrional info per cookie:143 calories, 7g fat, 3g protein, 18g carb, 1g fiber. And a quote: “I want to know where you find a bowl large enough to mix that much cookie dough.”