banana streusel cake

Ingredients

• 6 tablespoons all purpose flour
• 6 tablespoons firmly packed light brown sugar
• 3 tablespoons unsalted butter, cut into little pieces
• 1/4 teaspoon ground cinnamon
• 1/4 teaspoon kosher salt
• 2 cups cake flour
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon kosher salt
• 1 cup mashed banana (2 medium or 3 small or 9 oz)
• 3 tablespoons whole milk
• 1 teaspoon pure vanilla extract
• 4 oz (1 stick) unsalted butter, room temp
• 1 cup sugar
• 1 large egg, lightly beaten, room temp
• mini chocolate chips 2/3's cup (or more or less to your taste)