Preheat the oven to 350 degrees F. Using cooking spray with flour (like Baker's Joy), generously spray inside of a non-stick 12-cup bundt pan. Set aside.
Dissolve the instant coffee in the 1/2 cup of warm water.
In a large mixing bowl, mix the cake mix, pudding mix, eggs, sour cream, prepared coffee, and canola oil using a hand mixer on low speed. Scrape down the sides of the bowl. Continue to beat for 2-3 minutes on medium speed until the batter is thick and well combined. Use a rubber spatula to fold in the chocolate chips by hand.
Pour the cake batter into the prepared bundt pan and smooth the top so it's level with a spatula.
Bake for 45-50 minutes, or until a toothpick inserted halfway between the wall and the tube comes out clean. (There may be some melted chocolate on the toothpick from the chocolate chips, but there should be no wet batter.)
Remove the cake from the oven and let it cool in the pan for 10 minutes. Then, invert the bundt pan onto a wire rack until cooled, about 20 minutes. Transfer the cake to a serving platter.
Add the butter, salt, cocoa powder, and milk to a small saucepan, stir, and place over medium-low heat. Heat the mixture until just beginning to boil, then remove from the heat. Beat in the powdered sugar until the icing has thickened.
Pour the chocolate icing over the cake. (I used about 3/4 of the icing on the cake and then dipped strawberries in the rest. Yum!)
Working quickly, grate chocolate over the top. (The icing sets up quickly, so you want to get the chocolate on while it'll still stick.) Allow the icing to cool and set up. Cut into slices and serve with strawberries and whipped cream if desired.
Notes
Nutritional information is for the cake and icing only. It does not include the chocolate shavings or strawberries as these are optional garnishes.
If you don't want to use instant coffee, you can brew a strong cup of coffee and use 4 ounces instead of the warm water + instant coffee.
You can grate the chocolate ahead of time and sprinkle it over the cake once the icing has been poured on.
I like to cut the strawberries I put on the cake in half and place them cut side up. You can also serve whole, halved, or chocolate-dipped strawberries with a slice of cake on a plate instead.