Oven-roasted Sausages, Potatoes, and Peppers

package (at least 1 lb) of your favorite sausage links (johnsonvilles, evergood, generic smoked sausage, whatever you like.  i used polish sausages, 4 to a pack)

decent-sized potatoes (i prefer yukon gold or red bliss)

small jar banana peppers

bell peppers, sliced

large onion, sliced

olive oil (yes, it has to be OLIVE oil)

salt & pepper

*optional — 2 tsp dried rosemary

*optional — 3 tbsp creole seasoning