This is one of those recipes that I have trouble posting because looking at the photos makes me want to go make it again. So good! It’s basically a portobello burger (do you call them portobellos or portobellas? I’ve seen it both ways, I’ll stick with O for now.) with vegan mayo (add chipotle to make it spicy!), lettuce, tomato, and a bunch of shoestring onion rings – totally indulgent gourmet burger fare but with a lot less fat than you might expect.
It’s also pretty easy – the most involved part is making the breaded onion things, but you can also have a bunch of regular onion rings as a side dish so it’s worth the time. The burger would totally work without them, but who wants to pass up the opportunity for crazy delicious onion rings?
For the onion strings, it’s basically just Isa Chandra’s recipe but instead of slicing the onion into 3/4 inch slices you slice it as thin as you can and then cut the slices in half. Dip them in the sauce and sprinkle them with a bunch of bread crumbs.
It’s ok if they kind of stick together in a big mass – you can separate them a bit after you bake them. For two burgers I used about a third of a big onion. You can slice the rest of it into rings and just make the regular onion ring recipe as a side dish. In the photo below the onion strings are on the left and the onion rings are on the right – I used one big onion and had this sheet and another cookie sheet full of onion rings.
While those are baking you can preheat the grill and brush your portobellos with a bit of balsamic vinegar on both sides. Make sure you grease the grill well, these will want to stick a bit. Just grill them on medium for 3-4 minutes per side (you could probably also broil them for a few minutes per side, they just won’t have those sexy grill marks on them.)
Once the burgers and the onion rings are done (if you can’t get them to time out exactly right I’d say to err on the side of having the portobellos finish first, the onion rings get cold fast once they are done. You could also leave the onion rings in the turned-off oven if they need to sit for a few minutes) just assemble your burger (I put the chipotle mayo on the bottom bun, then the lettuce, then the portobello, then the tomato, then the onion strings on top. I doubt the order is terribly important, though.)
Serve while everything is still nice and hot and enjoy! What are your favorite burger toppings? Any suggestions I should try?
Vegan Portobello Burgers with Chipotle Mayo and Onion Strings
For the Onion Strings:
- 1 large or 2 medium vidalia onions about a pound, or other sweet onion like Walla Walla
- 1/2 cup plus 2 tablespoons all purpose flour I have used brown rice or amaranth flour to make this GF
- 2 tablespoons corn starch
- 1 cup cold almond milk or soy or rice milk
- 1 teaspoon apple cider vinegar
- 1 cup whole wheat bread crumbs I just toss a hamburger bun in the food processor to make about a cup of breadcrumbs. If you are using a GF hamburger bun that should work great.
- 1 teaspoon kosher salt
- 2 teaspoons olive oil
For the Burgers:
- Two portobello mushrooms stems removed
- 1 Tbsp balsamic vinegar
- 2 hamburger buns plus one extra if you are making the onion strings, see above
- 2 leaves romaine or other lettuce
- 1 to mato cut into 1/2 inch slices
- 1 recipe Vegan Chipotle Mayo
- Preheat oven to 450 degrees. Combine flour, corn starch, almond milk, and apple cider vinegar in a medium bowl. Peel your onion and slice about a third of it into very thin rings (as thin as you can get them) and then cut those rings in half. Slice the remainder of the onion into 3/4 inch rings to make onion rings. The breading process is roughly the same for the strings and the rings - dip the thin onion slices into the flour/almond milk mixture and then sprinkle thoroughly with breadcrumbs. Try not to get the breadcrumbs wet or they won't stick as well (so the idea is to sprinkle them over the wet onions, as opposed to dipping the onions right in the bowl.) Set them on a well-greased or parchment lined cookie sheet. Bake for 8 minutes on one side, flip, and bake for an additional 6 minutes on the other side, or until they are golden brown and crisp.
- While the onion rings are baking, heat your grill to medium and brush your portobellos with balsamic vinegar. Oil your grill and cook them for 3-5 minutes per side or until they are slightly softened and browned. You can also toast your buns by putting them on the grill for about 30 seconds, if you want.
- Once your onion strings and portobellos are done assemble your burger - about a teaspoon of chipotle mayo, lettuce, portobellos, onion strings. Serve and enjoy!