Ritz-Crusted Balsamic Salmon

1/2 medium yellow onion, chopped
5 to 6 tablespoons balsamic vinegar
4 tablespoons olive oil
2 salmon filets
6 Ritz crackers, finely crushed
Grated Parmesan cheese
Garlic powder, to taste
Lemon pepper, to taste
Oregano, to taste

Saut