Peanut Butter Cup Overload Cake

Name: Peanut Butter Cup Overload Cake
Prep time: 3 h
Cook time: 32 min
Total time: 3 h 32 min
Cuisine: American
Ingredients: 2½ cups + 1 tablespoon all-purpose flour; 3 cups granulated sugar; 1 cup + 1 tablespoon Dutch-process cocoa powder; 1 tablespoon baking soda; 1½ teaspoons baking powder; 1½ teaspoons salt; 3 eggs (at room temperature); 1½ cups buttermilk (at room temperature); 1½ cups strong black coffee (hot); ¾ cup vegetable oil; 4½ teaspoons vanilla extract; 2 cups powdered sugar; 2 cups creamy peanut butter; 10 tablespoons unsalted butter (at room temperature); 1½ teaspoons vanilla extract; ½ teaspoon kosher salt; ⅔ cup heavy cream; 8 ounces semisweet chocolate (finely chopped); ¾ cup heavy cream; 30 miniature peanut butter cups (coarsely chopped, divided)