Black Sesame Banana Cake Trifle

Name: Black Sesame Banana Cake Trifle
Ingredients: 1 1/2 cups all-purpose flour (about 6 3/8 ounces); 3/4 cup black sesame powder (about 2 3/4 ounces) (such as Lam Sheng Kee Foods); 1 teaspoon kosher salt; 1 teaspoon baking soda; 1 teaspoon baking powder; 1 cup salted butter (6 1/2 ounces), at room temperature, plus more for greasing pan; 1 cup granulated sugar; 1/4 cup plus 2 tablespoons well-stirred jarred black sesame tahini (such as Kevala); 2 large eggs; 1 cup mashed bananas (from 3 bananas); 1/2 cup well-shaken and stirred coconut milk (from 1 [13.5-ounce] can); 12 cups water; 3/4 cup sago or small pearl tapioca (such as Bob’s Red Mill); 2 1/2 cups well-shaken and stirred coconut milk (from 2 [13.5-ounce] cans); 1/4 cup plus 1 tablespoon granulated sugar; 1/4 teaspoon kosher salt; 1/2 cup plus 2 tablespoons granulated sugar; 3 cups heavy cream, divided; 1/4 cup plus 2 tablespoons well-stirred tahini; 1/2 teaspoon kosher salt; 1 medium (6-ounce) banana , sliced (about 3/4 cup); 1/4 cup toasted unsweetened flaked coconut