Spicy Sweet Potato Wedges

2 lb. sweet potatoes, cut into wedges;

1 tbsp. olive oil;

1 tbsp. mixed or black peppercorns, ground;

2 tsp. dried sage;

1 tbsp. dried oregano;

1 tbsp. dried thyme;

2 tbsp. paprika;

1 tsp. cayenne pepper;

3 tsp. garlic powder;