Step 1

Preheat the oven to 325ºF (170ºC).

Step 2

Butter and flour a 9- by 13-inch (22x33 cm) and set aside.

Step 3

Bring 1 ½ cups water to a boil. Put 2 cups Medjool dates and 1 teaspoon baking soda in a medium bowl. Add the boiling water and set aside until needed.

Step 4

Sift 1 ¾ cups all-purpose flour, ¼ cup unsweetened cocoa powder, remaining ¾ teaspoons baking soda and ½ teaspoon salt over a bowl and set aside.

Step 5

Beat ½ cup unsalted butter and 1 cup sugar with an electric mixer in a large bowl (or in the bowl of a stand mixer fitted with the paddle attachment) at medium speed for 2 minutes, scraping down the sides of the bowl as needed.

Step 6

Beat on high for 1 minute, add 2 eggs, one at a time, beating well after each addition. Scrape the sides of the bowl as needed. Beat an additional 2 minutes.

Step 7

Add 1 teaspoon vanilla extract and mix well.

Step 8

Add the sifted dry mixture and beat on low until well combined.

Step 9

Add the cooled date mixture and continue to beat for 30 seconds. Remove mixer and thoroughly combine with a spatula.

Step 10

Pour into prepared pan, spreading evenly, including corners.

Step 11

Bake for 20 minutes, until the cake starts to dry and rise.

Step 12

Take out of the oven, quickly sprinkle 2 cups semisweet chocolate chips on top, then 1 cup walnuts and return to the oven to bake for another 20 to 25 more minutes, until a cake tester or toothpick inserted in the center comes out clean. Remember you have the chocolate chips on top, not to confuse with uncooked batter.

Step 13

Remove the cake from the oven and let it cool on a wire rack.

Step 14

I like eating it the next day because it tastes much better. I like to refrigerate it for at least 20 minutes before serving to firm it up, but the chips and walnuts harden, as a reader commented, so she prefers not to. Your choice.