Preheat oven to 350 degrees F (175 degrees C). Line 2 mini muffin tins with mini paper liners.
Sift together flour, baking powder, and salt together into a bowl. Beat butter, white sugar, egg, and vanilla extract in a separate bowl with an electric mixer at medium speed until creamy, about 3 minutes. Beat flour mixture into creamed butter mixture, keeping mixer on low speed, until smooth. Add coconut milk and beat until batter is smooth; fold in shredded coconut.
Spoon rounded tablespoons batter into prepared muffin cups.
Bake on the center rack of the preheated oven until a toothpick inserted into centers comes out clean, 15 to 18 minutes. Transfer cupcakes to a rack to cool completely, 20 to 30 minutes.
Mix confectioners' sugar, passion fruit nectar, and cream together in a small bowl until smooth. Dip tops of cupcakes into icing, letting excess drip off. Let icing set for 2 minutes; garnish with flowers.
Substitute passion fruit syrup or thawed passion fruit puree, if desired.
Cupcakes can be made 1 day ahead and kept in an airtight container at room temperature. If you're garnishing with flowers and plan on icing the cupcakes ahead, save a bit of the icing for dipping and gluing the flowers onto the cupcakes.
Keep flower-garnished cupcakes at cool room temperature for no more than 3 hours or the flowers will wilt.
Per Serving: 204 calories;8.7 g fat;
30 g carbohydrates;
2.1 g protein;
30 mg cholesterol;
103 mg sodium.