Preheat oven to 350 degrees.
In the bowl of an electric mixer, whip egg whites and Cream of Tartar to soft peaks.
Slowly add sugar, a little at a time, so it gets incorporated into the soft egg whites. Continue beating on high until the whites are glossy, bright white and at the stiff peak stage.
Carefully fold in pecans and chocolate using a rubber spatula.
Spoon teaspoonfuls of the mixture onto an ungreased, 9X13 baking sheet. You should have approx. 18-24 depending on the size, and they should all fit on one sheet.
Place in oven, close door, then turn off the oven and 'forget' about them for 4 hours!
After 4 hours, remove from oven. Using a thin spatula, carefully lift each off the baking sheet and serve. Store in an airtight container, separated by wax paper for up to a few days.