In a bowl, mix pudding powder with sugar (follow the package pudding instructions) and a small amount of coconut milk until smooth.
Heat the remaining coconut milk in a saucepan over medium-high heat until it reaches a boil (100°C / 212°F).
While stirring constantly, pour the pudding mixture into the boiling coconut milk.
Continue stirring and bring back to a boil (100°C / 212°F) in about 1-2 minutes, then remove from heat.
Pour the pudding into a serving dish and press plastic wrap directly onto the surface to prevent a skin from forming. Cool to room temperature for 20-30 minutes.
In a separate bowl, beat the cream with 1 tablespoon of sugar on medium speed for 3-5 minutes until stiff peaks form.
If using fresh pineapple, peel and cut into small pieces; if using canned pineapple, drain the liquid thoroughly.
Gently fold the pineapple pieces and whipped cream into the cooled pudding until just combined.