Toast the nuts in a large skillet and let them cool completely.
Using an electric mixer, cream the butter and both sugars; Beat in the vanilla, then beat in your choice of 1) lemon juice or 2) dissolved espresso. I used lemon juice. Add the egg and egg yolk and beat just until eggs are until blended into the batter.
In a separate bowl, thoroughly stir together the flour, baking powder, baking soda and kosher salt. Add the flour mixture to the batter and mix just until well-blended. Add the oats to the batter and stir just until blended. Stir in the cooled chopped nuts and chocolate
Chill the dough for at least an hour. Note: I portion it first. By that I mean I scoop it onto plastic wrap lined dinner plates, cover and refrigerate until firm.
Preheat oven to 325 degrees F.
Spoon large tablespoonfuls of dough 3 inches apart onto ungreased cookie sheet; bake one sheet at a time for 13-15 minutes or until cookies are brown around edges but still soft in the middle. Allow them to sit on the cookie sheet for 3 minutes, then transfer to a rack to cool.
The yield is supposed to be 48 cookies, but I tend to make mine slightly larger and wind up with fewer.