Preheat oven to 350°F (180°C). Using a pastry brush, lightly brush bottom of a 13x9-inch baking pan with baking spray with flour. (Do not brush sides of pan.)

In a large bowl, vigorously whisk together flour, sugar, butter, coconut oil, eggs, baking powder, vanilla, and salt until well combined, about 5 minutes. Spread batter into prepared pan. Tap pan on a kitchen towel-lined counter several times to release any air bubbles.

Bake until golden brown and a wooden pick inserted in center comes out clean, about 20 minutes. Let cool in pan on a wire rack for 30 minutes. Run a sharp knife around edges of pan to loosen cake.

In a liquid-measuring cup, whisk together coconut milk, cream of coconut, and cream until well combined.

Using a small wooden skewer, poke holes all over warm cake. Slowly pour coconut mixture all over cake. Let cool completely. Cover and refrigerate cooled cake for at least 4 hours or up to overnight.

Just before serving, spread Vanilla Whipped Cream onto cake, and garnish with flaked coconut, if desired. Cover and refrigerate for up to 3 days.