Be sure not to overbake these, they harden as they cool.

Cream the margarine, butter, and both sugars in a large mixer bowl until light and fluffy. Add the eggs, milk, and vanilla and beat until blended.

Sift the flour, baking powder, baking soda, and salt together and add to the butter mixture. Stir just until blended. Stir in oats. Fold in the chocolate and walnuts.

Refrigerate the dough covered for at least an hour (important). Pre-heat the oven to 350 degrees and grease cookie sheets.

Shape the dough into balls, using a rounded teaspoon for small cookies or a scant tablespoon for large. Flatten slightly into rounded disks. Place 2 inches apart on the prepared baking sheets. Bake until the edges are slightly browned but the cookies are still white, 8 to 10 minutes.

Remove from the oven and let cool on the sheets for 5 minutes. Remove to wire racks to cool completely.