Prepare the Pineapple Filling

1. In a small saucepan over medium heat, combine crushed pineapple, sugar, cornstarch, and lemon juice.
2. Stir continuously until the mixture thickens (about 5-7 minutes).
3. Remove from heat and let the filling cool completely.

2. Make the Cookie Dough

1. In a large bowl, beat butter, granulated sugar, and brown sugar until light and fluffy.
2. Add egg yolks and vanilla extract, mixing until incorporated.
3. Gradually add flour and salt, mixing until just combined.
4. Stir in shredded coconut evenly.

3. Shape the Cookies

1. Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.
2. Roll dough into 1-inch balls and place them 2 inches apart on the baking sheet.
3. Use your thumb or the back of a spoon to create an indentation in each cookie.

4. Fill and Bake

1. Spoon a small amount of the cooled pineapple filling into each indentation.
2. Bake for 12-15 minutes, until edges are lightly golden.
3. Cool on the baking sheet for a few minutes before transferring to a wire rack.