Old Fashioned Chocolate Cake

Cake
3 cups all-purpose flour
2 cups sugar
1/2 cup unsweetened cocoa powder
2 teaspoons baking soda
1 teaspoon table salt
2 cups hot water
3/4 cup vegetable oil
2 tablespoons white vinegar
1 tablespoon instant coffee granules
1 tablespoon vanilla extract
Glossy chocolate Icing
8 tablespoons unsalted butter
1 1/2 cups sugar
1 1/4 cups unsweetened cocoa powder
1 pinch salt
1 1/4 cups heavy cream
1/4 cup sour cream
1 teaspoon instant coffee granules
2 teaspoons vanilla extract

Preheat oven to 350 with rack in the center.
Spray two 8" round cake pans with nonstick spray.
Whisk dry cake ingredients together in a large mixing bowl.
Combine water, oil, vinegar, instant coffee granules, and vanilla in a large measuring cup.
Add to the dry ingredients and whisk until combined- a few lumps are ok.
Divide batter between the two pans (about 3 cups each), then bake until toothpick inserted in center comes out clean (35- 40 min).
Cool cakes for 15 minutes on a rack, then invert them onto the rack.
Leave upside down until completely cooled before frosting them.
To make icing, melt butter in large saucepan over medium heat.
Stir in sugar, cocoa, and salt- the mixture will be thick/grainy.
Combine cream, sour cream and coffee granules in a large measuring cup, mixing until smooth.
Gradually add cream mixture to chocolate until blended and smooth.
Cook until sugar has dissolved, and mixture is smooth and hot to the touch.
DO NOT BOIL.
Take mixture off the heat, and add vanilla.
Cool at room temperature until spreadable (up to three hours).
If it isn't getting thick enough to be spreadable, put in the refrigerator until thick enough to spread.
If it gets too thick to spread easily, warm gently in the microwave until it's just right (20 seconds or so, repeat if necessary).
Stir well, and ice cake, frosting first layer, then placing second layer on top, and icing the top and then the sides.