Pour half of the melted butter over the mushrooms.
Sprinkle half of the (dry) ranch dip mix over the mushrooms.
Add remaining mushrooms to the crock-pot.
Pour the remaining melted butter over the mushrooms.
Sprinkle the remaining dip mix over the mushrooms.
Place lid on crock-pot, and cook on low for 3 - 4 hours. (I just cook mine for 3 hours, as after three hours of cooking time, my kitchen as well as the mushrooms smell so good, that we can't wait to dig into 'em.)
*Note: Hidden Valley has 2 kinds of seasoning mixes, a mix to make dips, and a seasoning mix to make salad dressing. For this recipe, I much prefer to use the dip mix.