Activate Yeast: Mix warm milk, yeast, and sugar. Let sit 5–10 minutes until foamy.

Make Dough: Combine flours, salt, eggs, zucchini, and yeast mixture. Add butter gradually and knead until smooth and elastic. Let rise 1–1.5 hours until doubled.

Prepare Filling: Mix butter, sugar, and cinnamon. Fold in zucchini and pineapple.

Assemble Rolls: Roll dough into a rectangle. Spread filling over dough. Roll tightly and cut into 8–10 pieces.

Second Rise: Place rolls in a greased pan. Cover and rise for 30–45 minutes.

Bake: Bake at 350°F (175°C) for 25–30 minutes, until golden brown.

Frost: Whisk powdered sugar, milk, and vanilla. Drizzle over warm rolls and serve.