Preheat the oven to 350°F (175°C). Line two standard muffin pans with cupcake liners.
In the bowl of a stand mixer, combine the strawberry cake mix, guava nectar, eggs, and coconut oil. Mix on low speed for 30 seconds. Scrape down the sides of the bowl, then beat on medium-high speed for 2 minutes until smooth. (Ignore the ingredients and directions on the back of the cake mix box.)
1 box (15.25 / 432 g) strawberry cake mix, 1½ cups (360 ml) guava nectar, 3 large eggs, ⅓ cup (80 ml) coconut oil
Fill each cupcake liner about halfway full. Bake for 15 minutes, or until the tops spring back lightly when touched and a toothpick inserted into the center comes out clean. Transfer the cupcakes to a wire rack and cool completely.
To make the guava glaze, combine the guava nectar and sugar in a medium saucepan over medium heat and bring to a boil. In a small bowl, whisk together the cornstarch and water until smooth. Remove the guava mixture from the heat and whisk in the cornstarch slurry. Return to the heat, bring back to a boil, and cook for 1 minute, stirring constantly, until thickened. Refrigerate until completely cooled.
1 cup (240 ml) guava nectar, ¼ cup (50 g) granulated sugar, 2 tbsps (16 g) cornstarch, 2 tbsps (30 ml) water
For the cream cheese layer, beat the cream cheese until smooth and fluffy. Add the sugar and vanilla extract and mix until fully combined. Fold in the thawed Cool Whip until no streaks remain.
10 oz (283 g) full fat, block cream cheese, ½ cup (100 g) granulated sugar, 1 tsp (5 ml) vanilla extract, 8 oz (226 g) Cool Whip
Spread an even layer of the cream cheese mixture over each cooled cupcake. Refrigerate for 20 to 30 minutes, or until the topping has firmed slightly.
Spoon the cooled guava glaze over the cream cheese layer, spreading it evenly across the top of each cupcake. Sprinkle with shredded coconut, if desired.
3 tbsps (15 g) sweetened shredded coconut
Refrigerate until ready to serve.