Veggie burgers--need a tweak

So last night I tried my hand at making black bean burgers.  The taste was fabulous!  But the texture was a bit mushy.  Hopefully you guys have some suggestions that can put them over the top.

I got the idea from Allrecipes.com.

My version:

Ingredients

• Big can (25.6 oz) of Bush's black beans
• half an onion
• whole bell pepper
• 2 tsp minced garlic
• 1 tbs Tony's
• 1 tbs ground cumin (my new favorite spice)
• 1 egg
• 1/2 cup Italian bread crumbs
• sliced Provolone cheese

Steps:

1. Drain, rinse, and dry can of black beans. Then mash them (a hand masher works best)
2. Mince onion, pepper, and garlic in a food processor.  Then add to the bean mix.
3. Add spices, egg, and bread crumbs to the mixture. Form 5-6 patties.
4. Pan fry on medium head for about 5 minutes each side.  Put cheese on top, lower heat, and cover the pan.  Let cook for about 3 more minutes.
5. Serve and enjoy!

The burgers were pretty mushy.  I really loved the taste of these, so I hope you try them out!

Any tips on how to make the burgers more sturdy?