Toast the pecans in a skillet over low heat. Watch them carefully to make sure they don't burn.
In a food processor, grind the oats, but don't totally pulverize them.
Place the oats in a bowl, and then sift in the flour, baking soda, and salt.
In the bowl of the electric mixer, cream the butter and sugars together until they're just blended. Add the eggs, vanilla, and lemon juice. Just mix until everything is blended.
Now add the oats and flour mixture, and just mix until no streaks of flour remain. Now add the nuts and chocolate chunks.
Chill the dough for one hour in the refrigerator.
Preheat the oven to 350 degrees. Line two baking sheets with parchment paper.
Then, form the dough into 24 balls. Each ball should contain a quarter of a cup of dough, or 60 grams.
Bake the cookies on the two middle racks, with six cookies per pan. Bake for 15 to 17 minutes, until the cookies are brown on the edges and the middles are set. Cool on a wire rack. Then, let the sheets cool completely and bake the next 12 cookies.