Heat the oven to 350°F. Lightly oil a square baking dish that measures 9 by 9 inches and leave it to the side.
In a big bowl, mix the pineapple with its juice, sugar, eggs, cornstarch, and vanilla until everything is well mixed.
Pour the pineapple mixture into the baking dish that has been prepared. Put small pieces of butter on top and sprinkle with cinnamon.
Cook in the oven for 45 minutes, until the sides are bubbling and the top is slightly golden.
Let it cool for 5-10 minutes before serving warm, or refrigerate it completely to serve cold.
Add whipped cream or vanilla ice cream on top, if you like.
Written reminders.
To give it a tropical flavor, add 1/2 teaspoon of coconut extract along with the vanilla.
Put a few maraschino cherries or toasted coconut on top to add color and crunch.
Make it more fun by adding a bit of pineapple rum before serving!