Melted is the past tense and past participle of the verb melt.
It can also function as an adjective, especially for substances that soften or liquefy at relatively low temperatures. Examples (verb):
She melted the butter in the pan.
The snow melted quickly under the sun. Examples (adjective):
Melted chocolate was perfect for dipping strawberries.
The recipe calls for melted cheese on top.
He cleaned up the spilled wax from the melted candle. Molten
Molten is used only as an adjective in modern English.
It typically describes substances that have been liquefied by extremely high heat, such as metals, glass, or rock. Examples (adjective):
The molten lead was poured into the mold.
Rivers of molten lava flowed down the volcano.
The artist shaped molten glass into a vase. Summary:
Use melted for everyday substances like butter, chocolate, cheese, or wax.
Use molten for materials transformed by intense heat, such as lava, glass, or metals.
For substances that do not require extremely high temperatures to melt, ""melted"" is the appropriate adjective. For example: melted chocolate, melted cheese, melted butter, melted wax.
e.g.: The melted chocolate was perfect for dipping strawberries.