For the Cake:

2 1/2 cups all-purpose flour
2 tsp baking powder
1/2 tsp salt
1 1/2 sticks unsalted butter, softened
1 1/2 cups sugar
2 eggs
2 tsp vanilla
1 1/4 cups buttermilk

For the Cinnamon Sugar Swirl:

1/2 stick unsalted butter, melted
1/4 cup light brown sugar, packed
1 Tbsp sugar
1 tsp cinnamon

For the Streusel topping:

3/4 cup all-purpose flour
1 stick unsalted butter, softened
1/2 cup light brown sugar, packed
1 tsp cinnamon