Prepare Mango Puree: Thaw 1 cup frozen mango chunks and blend until smooth, about 30-60 seconds. Pour into a fine mesh sieve over a bowl, pressing to collect smooth puree. Measure 1/4 cup (60 g).
Preheat & Prep: Preheat oven to 350°F (175°C). Line two baking sheets with parchment paper. Chop dried mango into 1/4-inch pieces.
Mix Dry Ingredients: In a medium bowl, whisk all-purpose flour, baking soda, salt, and shredded unsweetened coconut. Set aside.
Cream Butter & Sugars: In a stand mixer with paddle attachment (or hand mixer), cream unsalted butter, granulated sugar, and light brown sugar on medium speed for 2-3 minutes until light and fluffy. Scrape bowl as needed.
Add Wet Ingredients: Mix in egg yolk, vanilla extract, and mango solids on low speed until combined, about 1 minute.
Form Dough: Gradually add dry ingredients to wet mixture in two batches, mixing on low until just combined. Fold in dried mango and white chocolate chips with a spatula.
Shape Cookies: Using a 1 ½ tbsp cookie scoop, portion dough and place 2 inches apart on baking sheets (12 cookies per sheet). Gently flatten each ball slightly.
Bake: Bake one sheet at a time for 11-13 minutes, until edges are golden and centers are soft. Rotate sheet halfway through. Cool on sheet for 5 minutes, then transfer to a cooling rack.
Serve: Enjoy warm or at room temperature. Store in an airtight container for up to 4 days or freeze for 3 months.