Dark Chocolate Mousse Cake

Ingredients

• 1 and 3/4 cups (219g) all-purpose flour (spooned & leveled)
• 3/4 cup (62g) unsweetened natural cocoa powder* (see note)
• 1 and 3/4 cups (350g) granulated sugar
• 2 teaspoons baking soda
• 1 teaspoon baking powder
• 1 teaspoon salt
• 2 teaspoons espresso powder (optional)*
• 1/2 cup (120ml) canola or vegetable oil
• 2 large eggs, at room temperature
• 3/4 cup (180g) full fat sour cream, at room temperature
• 1/2 cup (120ml) buttermilk, at room temperature*
• 2 teaspoons pure vanilla extract
• 1/2 cup (120ml) hot water or coffee*
• optional: 1 cup (180g) mini or regular semi-sweet chocolate chips
• optional garnish: fresh berries and/or chocolate shavings
• 1/2 cup (120ml) hot water
• 1/4 cup (22g) unsweetened cocoa powder* (see note)
• two 4-ounce quality semi-sweet chocolate bars (113g each), finely chopped*
• 2 cups (480ml) heavy cream or heavy whipping cream
• 2 Tablespoons (15g) confectioners’ sugar
• 1/2 teaspoon pure vanilla extract
• 1 cup (240ml) heavy cream or heavy whipping cream