The Kitchn: For the best chocolate cake of your life, never skip this one easy step
1 teaspoon kosher salt
1 3/4 cups all-purpose flour
1 3/4 cups granulated sugar
3/4 cup natural cocoa powder
1 tablespoon instant espresso powder
2 teaspoons baking soda
2 teaspoons baking powder
1/2 cup boiling water
For the frosting:
3 sticks (12 ounces) unsalted butter
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