Gooey Cinnamon Cake

Name: Gooey Cinnamon Cake
Ingredients: 1 1/2 cups (190g) flour; 2 teaspoons baking powder (aluminum-free); 1/4 teaspoon salt; 8 tablespoons (115g) unsalted butter, at room temperature; 3/4 cup (150g) sugar; 1 large egg, at room temperature; 1/4 cup (60ml) whole milk; 1/4 cup (60ml) light corn syrup or golden syrup; 1/4 cup (60ml) whole milk or heavy cream; 1 tablespoon vanilla extract; 12 tablespoons (170g) unsalted butter, at room temperature; 1 cup plus 2 tablespoons (225g) sugar; 1 1/4 (155g) cups flour; 2 tablespoons sugar; 1 1/2 teaspoons ground cinnamon