Espresso Streusel Coffee Cake

Ingredients

• Batter
• 1 stick unsalted butter, at room temperature
• 1 cup granulated sugar
• 2 large eggs
• 2 cups all-purpose flour
• 1 teaspoon baking powder
• ¼ teaspoon baking soda
• ½ teaspoon kosher salt
• 1 cup sour cream
• Streusel
• 1 cup dark brown sugar, packed
• 2 teaspoons instant espresso powder (not instant coffee)
• 2 teaspoons ground cinnamon
• 2 teaspoons vanilla extract
• 1 ½ cups all-purpose flour
• 8 tablespoons unsalted butter, melted