Double Chocolate Peanut Butter Lava Cake

Ingredients

• 1 stick plus 1 tablespoon unsalted butter, plus melted butter for brushing
• 1 tablespoon unsweetened cocoa powder
• 1/4 cup plus 1 tablespoon all-purpose flour
• 6 ounces dark chocolate (70 percent cacao), chopped
• 3 tablespoons creamy peanut butter
• 1 tablespoon confectioners’ sugar, plus additional for garnish
• 1/2 cup granulated sugar
• 3 large eggs, at room temperature
• Pinch of salt