Before cooking: Remove butter from the fridge and allow it to soften to room temperature.
Pre-heat the oven to 400ºF.
In a mixing bowl, add softened butter, garlic, shallot, parsley, white wine, salt, and pepper. Use a rubber spatula to thoroughly mix butter together.
Use a small spoon or a teaspoon measure to add the garlic butter either into the empty shells or into the bottom of the baking dish. Top that pat of garlic butter with the drained escargot, then another teaspoon-sized scoop of garlic butter. If using shells, it should be 1 scoop of butter, 1 escargot, then 1 more scoop of butter. Ensure the escargot is fully covered in the butter.
Bake in a pre-heated 400º F oven for 10-12 minutes or until the garlic is cooked and the butter is beginning to brown on the edges. Cool slightly, then serve.