1. In a medium bowl, combine 13/4 cups of the flour, the baking powder, baking soda and salt. In small bowl, blend cocoa and remaining 1 cup flour.
2. Begin layering: Spoon half the flour-cocoa mixture into jar. Press down to flatten (a small spice jar works well). Spoon half the plain flour mixture over cocoa layer; compact. Repeat. Top with brown sugar layer and granulated sugar layer, compacting each. Spoon M&Ms over sugar.
3. Toss together both kinds of chips in a small bowl and add to jar. Attach a note with baking instructions: In large bowl, combine 1 cup (2 sticks) cooled, melted unsalted butter with 3 eggs, 1/3 cup milk and 2 tsp vanilla extract. Stir in contents of jar just until mixed. Drop dough by heaping tbsp onto baking sheets. Bake at 350 degrees for 13 minutes or until firm. Cool on sheet on wire rack for 1 minute. Remove directly to rack to cool completely.