Preheat oven to 350°F (180°C).

In a medium bowl, whisk together 1⅓ cups (167 grams) flour, salt, baking powder, and baking soda.

In a large bowl, whisk together eggs and sugars until light and fluffy, about 2 minutes. Add oil, buttermilk, and vanilla, and whisk until well combined, about 1 minute. Fold in flour mixture until well combined.

In a small bowl, toss together pineapples, cherries, and remaining 2 tablespoons (16 grams) flour until fruit is well coated in flour. Fold fruit mixture into batter until well combined.

Spray a 6-cup charlotte cake pan with baking spray with flour. Spread batter into prepared pan.

Bake until a wooden pick inserted in center comes out clean, 45 to 50 minutes. Let cool in pan for 10 minutes. Invert cake onto a wire rack, and let cool completely.

Spread Cherry Hibiscus Curd in center of cooled cake. Garnish with cherries, if desired. Cover and refrigerate for up to 3 days.