I love these cookies. They always come out so soft and chewy (hence the name!). I doubled the recipe because I wanted to send some to daycare with my daughter to share with her friends. I think it's important to use real butter and not margarine. I tried using margarine once and it just wasn't the same. Source: Alton Brown
2 sticks unsalted butter (I used salted)
2 1/4 cups bread flour
1 teaspoon kosher salt (I cut back to 1/2 teaspoons since my butter was salted)
1 teaspoon baking soda
1/4 cup sugar
1 1/4 cups brown sugar
1 egg yolk
2 tablespoons milk
1 1/2 teaspoons vanilla extract
2 cups semisweet chocolate chips (I used 1 1/2 cups of chocolate chips and 1/2 cup of mini Reeses Pieces)
Hardware: Ice cream scooper (#20 disher, to be exact) (I didn't use this, just regular spoons)
Heat oven to 375 degrees F. Melt the butter in a heavy-bottom medium saucepan over low heat. Sift together the flour, salt, and baking soda and set aside. Pour the melted butter in the mixer's work bowl. Add the sugar and brown sugar. Cream the butter and sugars on medium speed. Add the egg, yolk, 2 tablespoons milk and vanilla extract and mix until well combined. Slowly incorporate the flour mixture until thoroughly combined. Stir in the chocolate chips. Chill the dough, then scoop onto parchment-lined baking sheets, 6 cookies per sheet. Bake for 14 minutes or until golden brown, checking the cookies after 5 minutes. Rotate the baking sheet for even browning. Cool completely and store in an airtight container.
Since I did a double batch, I always put the dough back in the fridge between batches.