I took the recipe from allrecipes.com and tweaked it a little bit.
1 1/4 c. flour
1 tsp. salt
1 tsp. baking powder
2/3 c. brown sugar
2/3 c. white sugar
2/3 c. cocoa powder
From here it should be fairly self-explanatory. You mix together the first three ingredients, then put them in a one-quart mason jar. Then layer each new ingredient on top, so it's all pretty in the jar, and fill it to the top with the pecans (or whatever you want to use, really. I imagine chocolate chips would work, or walnuts or whatever else sounds good to you). Then attach a tag that includes the instructions for baking. Mine says, "Instructions: 1) Add 2/3 cup vegetable oil, 1 teaspoon vanilla extract, 3 eggs. 2)Bake at 350 degrees F (175 degrees C) for 30 minutes in a lightly greased 9x9 pan." Or it will when I print them out. We were going to include something along the lines of, "if you need more instructions than that, you're too dumb to be our friend," but we have friends who are nicer than we are and we worried that would hurt their feelings.
Now, I have to warn you, if you try this recipe, I haven't actually made it yet. It'll be a grand adventure, finding out if it's any good or not. But doesn't the jar look so pretty??