You can also decide whether or not you want to add cornstarch along with the other dry ingredients. I find that it helps keep the cookies soft for a bit longer after they're baked, but if you're planning on eating them all right away you don't need to bother.
Whatever you decide to do, add the dry ingredients to the wet ingredients and mix slowly until just incorporated, scraping the sides of the bowl as needed.
Oatmeal Chocolate Chip Cookies
Source: Family recipe Yield: 4 dozen
1/2 cup of butter (room temperature)
1/2 cup of shortening
1 cup of brown sugar (packed)
1 cup of granulated white sugar
2 tsp of vanilla extract
2 cups of flour
1/2 tsp of salt
1/2 tsp of baking soda
Optional: 2 tsp of corn starch
2 cups of rolled oats
3 cups of semisweet chocolate chips
Cream together butter, shortening, and sugars for 2-3 minutes or until light and fluffy. Add the eggs and vanilla; mix until well incorporated and creamy.
In a separate bowl, combine the flour, salt, baking soda, and corn starch (if desired). Add dry ingredients to wet ingredients and stir until just combined. Mix in rolled oats and chocolate chips, stirring until combined.
Scoop out cookie dough in 1-1/2 Tbsp portions onto a cookie sheet lined with parchment paper, spacing them about 2 inches apart. Bake in a 350° F oven for 10-12 minutes. Let the cookies cool on the pan for 2 minutes before transferring them to a wire rack to cool completely.
Store any leftover cookies in an airtight container or tupperware.