Black Bean and Mushroom Burgers

Yet again, as I was flipping through my saved recipes, I found this one from quite a while ago on Brown Eyed Baker (adapted from Culinary in the Country).  Theses burgers sounded absolutely delicious, especially along side of the fries I was already planning on making.  On Monday, I had a longer than normal day at work, and when I got home I was absolutely starving.  Once I started putting everything together for dinner, these burgers came together very quickly.  They were especially tasty topped with a little salsa and sour cream.

1 tablespoon Canola Oil, plus more for brushing
1 cup Onion, finely chopped
8 ounces Cremini Mushrooms, finely chopped
1 Garlic Clove, minced
1/2 teaspoon Cumin
1/2 teaspoon Smoked Paprika
4 slices Whole Wheat Sandwich Bread, lightly toasted (I used 4 ounces total-half panko, half bread)
1 (15 ounce) can Black Beans, rinsed and drained
2 ounces Cheddar Cheese, shredded
Salt & Pepper, to taste
4 Buns (I used Sandwich Thins)
Salsa & Sour Cream, for serving (optional)

In a large skillet, heat the oil over medium heat.  Add the onions and cook, stirring occasionally, until they begin to turn golden brown, about 4 minutes.  Stir in the mushrooms, garlic, cumin, and paprika and cook until the mushrooms have released their moisture, about 4-6 minutes.  Remove from heat and set aside to cool slightly.  Meanwhile, tear toasted bread pieces and place in the food processor.  Process until bread crumbs are formed.  Place them in a large bowl and set aside.  Add the mushroom mixture and beans to the food processor and pulse until combined, leaving some chunky bits.  Scoop the mixture into the bowl with the bread crumbs.  Add the cheese, salt, and pepper, mix all ingredients until well combined.  Divide the mixture into 4 equal portions and form into patties.  Lightly brush each side of the patties with canola oil.  Heat a grill pan or skillet over medium heat.  Place the patties on the surface and cook until completely heated through and the outside has crisped, about 5 minutes per side.  Serve burgers on toasted buns and top with salsa and sour cream, if desired.