1) Preheat the oven to 425°F. Lightly grease two baking sheets, or line them with parchment.
2) In a large bowl, beat together the butter, sugar, orange peel, vanilla, baking powder, and salt.
3) Beat in the egg. The mixture may look slightly curdled; that's OK.
4) Add the flour and dried cranberries (or cranberries and nuts), stirring until well combined.
5) Drop the dough by heaping teaspoonfuls onto the baking sheets, leaving about 1 1/2" between them. A level teaspoon cookie scoop works very well here; dough balls will be about 1 1/4" in diameter. Using the flat bottom of a glass dipped in sugar, flatten the cookies slightly, to a scant 1/2" thick.
6) Bake the cookies for 6 to 7 minutes, until they're barely set, and a light golden brown around the edges. Don't over-bake; if you do, the cookies will be hard, not soft and chewy. Gently lift one of the cookies and look at the bottom; if you've used parchment, it shouldn't be brown. If you're baking on a dark cookie sheet without parchment, it should be light (not dark) brown.
7) Remove the cookies from the oven, and cool them right on the pan. If you need a pan to bake the remainder of the cookies, give the cookies about 5 minutes to set before transferring them to a rack to cool completely.
Yield: about 4 dozen cookies.