Heat the oven to 350F. In an electric mixer, cream butter, peanut butter, and sugars until light and fluffy. Add egg and vanilla, and mix on medium speed until well-combined. Sift flour and baking soda together, then add to the butter mixture, beatinf just to combine. Fold in chocolate chunks.
Using a spoon, scoop out 1 1/2 ounces of the cookie dough to an ungreased baking sheet. Press down slightly to flatten. Bake until golden brown, 18-20 minutes.
Transfer to a wire rack and cool completely. Can be stored in an airtight container up to two weeks.
The first batch I made was so lousy coz I placed a big scoopful and didnt leave enough spaces between each cookie. This certain cookie dough can spread too widely in the sheet, so be careful with the spacing. Also, I found that waiting 18-20 minutes resulted in a burned bottom, so I suggest taking it out at 15 minutes instead. The original recipe says it makes 14 cookies, but on double-recipe I easily whipped out some 50 pieces.
I found some tin cans in Christmas colors, which came in handy for the packaging. I sure hope the teachers were happy with it :)