Great Great Aunt Jessie's 1940's Ice Box Cookies

Found this scribbled on a slip of paper in Great Great Aunt Jessie's recipes from the 40's and 50's. I am copying her scribblings here for preservations sake. I have not made these so I do not have exact times to share.

• Ready In: 18 mins
• Serves: 15

Ingredients

• 1⁄2 cup butter
• 1  cup brown sugar (or scant cup granulated sugar)
• 1⁄2 teaspoon vanilla
• 2  cups flour
• 1⁄2 teaspoon baking soda
• 1⁄2 teaspoon cream of tartar
• 1⁄2 cup  broken  nutmeats

Directions

1. Work 1/2 cup butter till creamy, 1 cup brown sugar- cream 1 cup or scant cup granulated sugar.
2. Mix well and add 1/2 teaspoon vanilla.
3. Sift 2 cups flour, 1/2 teaspoon soda and 1/2 teaspoon cream of tarter.
4. Add to first mixture.
5. Then add 1/2 cup broken nut meats.
6. Pack in bowl and put in refridgerator to cool slightly- then make out in rolls.
7. When very cold, slice and bake in temperature of 400*.
8. 8 minutes.
9. Aunt Jessie then scribbled"probably 15" to which I have no clue what that is referencing.