Here is the full list of all 21 White Lavender achievements.
Find the purple ball.
Cure your sister.
Collect all ingredients needed for the special tea.
Wear a hat that's way too big.
Wear all blue wizard items.
Collect 8 mug shards.
Get pranked.
Meet the mayor.
Find the four-leaf clover.
Explore all areas.
Defeat all boss enemies.
Take Meggie to the end
Reach 10 might.
Reach 10 witchcraft.
Reach 10 agility.
Wear sunglasses.
Collect all 3 holy scribbles.
Collect the pencil.
Cure your sister within 60 minutes.
Find the split pistachio helmet.
Find all kettles.