Preheat the oven to 220 Celsius (425 Fahrenheit) and line a roasting pan with baking paper. Toss the pineapple, sugar spices and Tequila in a bowl and mix to combine. Pour into the baking tray and roast for 20 minutes. Set aside to cool.
Place the milk and cream in a saucepan and bring to a boil. Add the vanilla bean and seeds and cover with a lid and set aside for 30 minutes.
Return the milk and cream to the heat and bring to the boil again. While you are doing this combine the egg yolks and sugar in the bowl of an electric mixer fitted with a whisk attachment. Whisk the egg yolks and sugar until combined and lightly thickened.
When the milk and cream has returned to the boil pour 1/3 of the mixture into the egg yolk mixture while the whisk is running at a low speed. This will temper the mixture to ensure that it doesn’t curdle. Then slowly pour the remaining milk and cream mixture into the mixing bowl with the whisk going all the while.
Pour the combined custard mixture back into the saucepan and return to the heat. Stir the mixture and check the custard by turning the back of the spoon and running your finger through the custard on the spoon and if the line stays clean and doesn’t run back into the line you’ve created then the custard is done.
Strain the custard through a fine mesh sieve into a large bowl and discard the vanilla bean. Cover the bowl with cling film and refrigerate for 3 to 4 hours. The custard mixture should be completely cold before churning.
Turn on your ice cream machine and carefully pour the mixture into the churn according to the manufacturers instructions.
While the ice cream is churning place 3/4 of the roasted pineapple into the bowl of a food processor fitted with a metal blade and puree.
When the ice cream is almost done slowly add the pineapple as the ice cream continues to churn. This will ensure that the fruit is evenly distributed through the ice cream.
When the ice cream is done pack into a large container and freeze for 2 hours before serving.