Preheat oven to 350 degrees. Line a 13x9-inch baking pan with parchment papr.

In a large bowl, stir together coconut, 1 can condensed milk, vanilla, and salt until well combined. Spread mixture in prepared pan.

Bake until edges are golden brown, about 30 minutes. Let cool completely. Tear macaroon into small pieces and set aside.

Prepare a large bowl of ice water for ice bath. In a medium saucepan, bring coconut milk, pineapple juice, ¼ cup water, and remaining 1 can condensed milk to a boil over high heat. Reduce heat, and cook at a rapid simmer, stirring frequently, until thickened, about 10 minutes. Remove from heat; stir in coconut extract. Place saucepan in prepared ice bath and stir until mixture is cool, about 4 minutes.

In a large bowl, beat cream at high speed until stiff peaks form, about 2 minutes. Gently fold whipped cream into coconut milk mixture. Divide among two (6-well mini) Bunt pans. Freeze until firm, about 6 hours. (makes 12)

Press macaroon pieces into each semifreddo forming an even layer. Freeze for 2 hours.

Let stand at room temperature for 5 to 10 minutes. Invert onto a serving platter. Garnish with pineapple pieces, if desired.