From a fantastic little book called "The Great Book of Chocolate" by David Lebovitz, these are called Blue Chip Chocolate Chip Cookies, and is apparently the recipe from a (now closed) shop called "Blue Chip Cookies" in San Francisco. As amended by me (to exclude nuts, since my son is allergic) :
1/2 cup (100g) white sugar
1/2 cup (120g) firmly packed light brown sugar
1 stick (115g) unsalted butter, cold, cut into 1/2 inch dice
1 large egg
1 tsp vanilla extract
1/2 tsp baking soda
1.25 cups (175g) all-purpose flour
1/4 tsp salt
2.5 cups (330g) dark chocolate Callebaut callets (you could just use cooking choc bits, but the Callebaut is designed to melt, and you get this gooey mass of melted chocolate in the cookie).
Interestingly, this recipe has about twice the chocolate to other ingredients as the Mrs Fields' recipe does.
1. Preheat oven to 300F (150C). Line baking sheets with parchment paper.
2. Beat cold butter and sugars together, until just combined. The secret is that the butter should still be cold. I find if you beat until the butter is completely creamed, you get cookies that spread too much. I'll usually have some small lumpy bits of butter left in my finished dough.
3. Mix in egg, vanilla and sifted baking soda.
4. Stir flour and salt together in a separate bowl, stir choc callets into the flour mix. Tip the whole lot into the batter, and mix until just incorporated (no bits of flour left). DO NOT OVERMIX.
5. Scoop balls of dough (2 Tbsp worth - say 2" balls) and place them on tray, about 4 inches apart.
6. Bake for 18 minutes, or until pale golden brown. Remove from rack, let it sit for a few seconds, then transfer and cool on rack. Cookies will be large and fragile when hot. Eat any broken ones, as they obviously have no calories. Store in an airtight container. If you live alone, freeze some, or you will be the size of a bus. Makes 16 - 20 large cookies.
