Super-Crumb Coffee Cake

Bahan-bahan (8 porsi)

• 1 Tablespoon all-purpose flour, for coating the pan
• 2 cups (250g) all-purpose flour (spooned & leveled)
• 1 cup + 2 Tablespoons (225g) granulated sugar
• 1 teaspoon salt
• 10 Tablespoons (142g) unsalted butter, firm and cold
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 3/4 cup (180ml) buttermilk, at room temperature
• 1 large egg, at room temperature
• 2 teaspoons pure vanilla extract
• 2/3 cup (133g) packed light or dark brown sugar
• 2 teaspoons ground cinnamon