Portobello Mushroom Burgers make a great summer dish. They're great for a BBQ, but they can also be done in a cast iron frying pan (that way you get the tasty looking grill lines).  My grandmother was a very old-school, European lady who grew up on meat and potatoes. After a lengthy stay in the hospital, my mom asked her what she'd like for her first dinner home, to our great surprise she replied "Portobello Mushroom Burgers". Not only are they tasty, but they're super easy to make.
Portobello Mushroom Burger with homemade coleslaw & asparagus
Portobello Mushroom Burgers:
4 portobello mushrooms (use the whole top as a 'pattie')
1 red/yellow/orange pepper & onion (optional)
1 clove of garlic
pinch of salt and pepper
olive oil
balsamic vinegar (to your taste)

Wash the mushrooms and cut off the stems. Place them in a large dish. Cut pepper & onion in large chunks, add them to the dish. Mince garlic, mix with balsamic vinegar and olive oil, pour marinade over veggies. Let stand for 10-15 minutes (or cover and put in the fridge till you're ready to start grilling). Grill for 5 minutes each side, mixing up the peppers & onions when needed. Place them on a bun (or on their own if you prefer no bread), with Veganaise & mustard, sprinkled with grilled veggies and slices of fresh tomato. Serve them with a side salad and/or greens.

Note: if you like to use a BBQ, you'll need a grill tray for the veggies
Vegenaise from Viva Vegan Store