In the Test Kitchen: Making Andrei’s chocolate cookies

Beating the eggs and sugar to the “ribbon” stage. When the beater is removed, the falling batter should form a slowly-dissolving ribbon on the surface of the batter in the bowl.  (Noelle Carter / Los Angeles Times)

Cooled melted chocolate. As the eggs and sugar are beaten in a separate bowl, the melted chocolate will cool, thickening to an almost paste-like consistency.  (Noelle Carter / Los Angeles Times)

After the espresso and vanilla are added, slowly add the melted chocolate to the beaten eggs.  (Noelle Carter / Los Angeles Times)

The melted chocolate almost fully incorporated with the beaten egg mixture.  (Noelle Carter / Los Angeles Times)

The cookie dough after the chopped chocolate is added. The dough should not be thin, but have a thick texture, similar to wet cement.  (Noelle Carter / Los Angeles Times)

When the dough is fully chilled, it will be thick enough to scoop or spoon, similar in texture to mousse or mashed potatoes. Here, the dough (about 2 tablespoons worth) is scooped onto parchment-lined double baking sheets.  (Noelle Carter / Los Angeles Times)

The cookies after about 2 minutes in the oven. The cookies will spread as they bake, and the dough will look as though it is melting.  (Noelle Carter / Los Angeles Times)

The cookies after about five minutes in the oven, as the dough continues to spread.  (Noelle Carter / Los Angeles Times)

The cookies after about eight minutes in the oven, as the dough continues to spread.  (Noelle Carter / Los Angeles Times)

Rotating the cookies halfway through baking. The dough will be very wet before it begins to set.  (Noelle Carter / Los Angeles Times)

As the cookies set, they will form a delicate crust and begin to puff and expand.  (Noelle Carter / Los Angeles Times)

The finished cookies. The outer crust is crisp, and the inside is soft and chewy. The cookies will firm up as they cool.  (Noelle Carter / Los Angeles Times)