Step 1

1 For the cookies: Preheat the oven to 350 degrees (to allow for a thoroughly heated oven)

Step 2

2 Line the bottoms of 2 baking sheets with parchment paper or silicone liners

Step 3

3 Place the confectioners' sugar in the bowl of a food processor and process with several short pulses to aerate it

Step 4

4 Add the almonds, and process for about 2 minutes, until the nuts are finely ground, stopping the motor every so often to break up any clumps that form in the bottom of the bowl

Step 5

5 Transfer to a large bowl, breaking up any clumps

Step 6

6 Beat the egg whites and cream of tartar in the bowl of a stand mixer or hand-held electric mixer on medium-low speed until frothy

Step 7

7 Increase the speed to medium-high and beat until soft peaks form; then, still beating, gradually add the granulated sugar

Step 8

8 Beat until the egg whites are glossy and voluminous and form stiff peaks

Step 9

9 Reduce the speed to low; dissolve the espresso powder in the water in a small cup, then add to the bowl and mix just to incorporate

Step 10

10 Use a spatula to fold half of the beaten egg whites into the sugar mixture to partially combine and lighten it

Step 11

11 Fold in the remaining beaten egg whites until no white streaks remain and they are completely incorporated; do not overmix

Step 12

12 Fit a large pastry bag with a 3/8-inch (1-centimeter) plain tip

Step 13

13 Spoon the batter into the bag

Step 14

14 Holding the pastry bag upright, pipe blobs of batter about 1 inch in diameter, spaced 1 inch apart on the prepared baking sheets; you should be able to fit 36 cookies on each sheet

Step 15

15 Let sit uncovered on a flat surface at room temperature for 30 to 60 minutes

Step 16

16 The tops will look smooth and lose their shine, and the batter will spread slightly

Step 17

17 Bake one sheet at a time on the middle rack for about 12 minutes or until the tops turn golden and feel firm and crisp when lightly touched

Step 18

18 If using a parchment paper liner, allow to cool for a couple of minutes, then peel the cookies from the paper by pressing them off from the underside

Step 19

19 Or, to ensure that the cookies release easily, as soon as you remove the baking sheet from the oven, carefully lift the parchment one end at a time and sprinkle a total of about 2 tablespoons of water under the paper, moving the paper around a little to distribute the moisture more evenly

Step 20

20 The steam will loosen the cookie bottoms from the paper

Step 21

21 After 3 minutes (and no longer), lift the paper liner from the baking sheet and peel the cookies from the paper

Step 22

22 If any of them stick, slide a thin metal spatula under the bottoms to loosen them

Step 23

23 If using a silicone liner, let the macarons rest on the lined baking sheet for 10 minutes, then peel off the macarons

Step 24

24 Transfer the macarons to a wire rack to cool

Step 25

25 Repeat to use all of the batter; you should end up with at least 120 bite-size cookies

Step 26

26 Meanwhile, make the filling: Heat the cream and butter in a medium saucepan over medium-low heat until the cream is hot and the butter has completely melted

Step 27

27 Do not let the mixture bubble or boil

Step 28

28 Remove from the heat

Step 29

29 Add the chocolate chips, making sure they are all submerged, and let them soften in the hot cream mixture for about 30 seconds

Step 30

30 Then stir until smooth and all of the chocolate is melted

Step 31

31 Let sit at room temperature for about 45 minutes or until the mixture thickens enough to hold its shape

Step 32

32 When ready to fill, turn half of the cooled macarons bottom side up

Step 33

33 Use a small rounded knife to spread about 1 rounded teaspoon of the filling over each cookie bottom, or use the pastry bag and tip to pipe the filling onto the cookies

Step 34

34 Press the flat bottoms of the remaining cookies onto the filling to create about 60 small macaron sandwiches

Step 35

35 (You may have a little filling left over

Step 36

36 ) Serve, or cover and store at room temperature or in the refrigerator for up to 3 days