Jodie's Filet-Arugula

1 Lb tenderloin
4 Tb olive oil (or less)         
2 Small shallots, chopped
4 Cloves garlic, sliced
1 Sprig rosemary chopped
3 Cups mushrooms , sliced
2 Tb Balsamic vinegar plus more for marinate
6 Oz. Arugula
Salt and pepper
Shaved Parmesan

Marinate tenderloin in balsamic vinegar
Cook shallots, garlic and rosemary in oil in pan with fond from trimmings.  Add mushrooms, salt and pepper. Cook til mushrooms begin to caramelize.
Meanwhile grill meat.
Add balsamic vinegar to pan. Off heat add arugula tossing to wilt. Top with balsamic reduction and shaved Parmesan.         

                    Balsamic Reduction
1/4 cup plus 2 Tb vinegar
2 Tb butter
2 Tb. brown sugar
2 Tb. Shallots, minced

Sauté shallots in butter. Add sugar and vinegar. Bring to boil and cook, stirring until reduced to your taste.