For the cupcakes: Preheat the oven to 350 degrees F. Line two regular-size cupcake pans with 24 cupcake liners.
In a large bowl, sift the flour, sugar, baking powder and salt together. Set the bowl aside.
In an electric stand mixer bowl fitted with a paddle attachment, add the milk, vegetable oil, 1 cup cold water, pineapple, vanilla extract and eggs. Beat the wet ingredients together on medium speed for 2 minutes. Add the dry mixture into the bowl in three additions, scraping down the sides after each addition is mixed in. Pour half of the cooled Brown Sugar Sauce into the mixer bowl. Mix on low to medium speed until all the ingredients are mixed together; the batter will look smooth.
Fill each cupcake liner three-quarters full with the batter. Bake on the center rack for the best results. Bake until a toothpick comes out clean, 25 to 32 minutes. Cool completely. The cupcakes will be golden.
To assemble: Poke a hole in the center of each cupcake, fill with the Pineapple Filling. Frost the cooled, filled cupcakes with the Teriyaki Buttercream Frosting. Finish the cupcakes with the Caramelized Roasted Pig.
In a medium saucepan, add the brown sugar, milk and butter. Heat on medium to high heat until the mixture bubbles and becomes thick enough to coat the back of a metal spoon, 10 to 15 minutes. Remove from the heat and pour into a heatproof bowl. Let cool.
Mix 1/2 cup cold water and the cornstarch in a small bowl with a fork. Puree the pineapple, brown sugar and the water mixture in a blender. Bring the mixture to a boil in a medium saucepan over medium to high heat. Stir with a wooden spoon until the mixture reduces down to a thick syrup. Remove from the heat and pour into a bowl. Cool the filling in the refrigerator. When cool, pour the filling into a squeeze sauce bottle.
In the bowl of an electric stand mixer fitted with the paddle attachment, beat the butter on medium speed until smooth. Scrape down the sides. Add the egg yolks one at a time to the butter, mixing in between each addition. Mixing on low speed, add the powdered sugar to the bowl 1 cup at a time, until the sugar is fully incorporated. Scrape down the sides again. Add the teriyaki sauce, half of the brown sugar sauce and vanilla to the mix, beat on medium low, 2 minutes.
In a small saucepan, melt the butter over medium heat. Add the brown sugar and stir until the sugar and butter melt together. Add the roasted pig, and stir until all the meat is coated with the mixture. Pour onto wax paper, and cool.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.