Grill-Grate Portobello Burgers
Marinated mushroom caps over coals, stacked with mozzarella and a jar of garlic mayo.
- calories
- 540
- weight
- 9 oz
- cal / oz
- 60
- protein
- 16 g
- serves
- 4, scales
- prep
- 20 min
- cook
- 10 min
- total time
- 30 min
- water
- none
- cost
- $$
Calorie and protein figures are my own estimates, good enough for planning a food bag and not meant as precise nutrition data.
- Dinner
- Grill grate
- Campfire coals
- Car camping
- Basecamp
- Nut free
- Foil packet
- Pre-mix at home
- Needs a cooler
- Basic
Ingredients
| Large portobello caps | 8 | stems twisted off at home |
|---|---|---|
| Balsamic vinegar | 1/2 cup | |
| Worcestershire sauce | 3 tbsp | most brands contain anchovy |
| Olive oil | 4 tbsp | 2 for the marinade, 2 for the aioli |
| Cayenne pepper | 1/8 tsp | |
| Salt and pepper | to taste | |
| Mayonnaise | 1/2 cup | single-serve packets travel better than a jar |
| Garlic, minced | 1 tbsp | |
| Lemon juice | 1 tsp | bottled is fine |
| Paprika | 1/4 tsp | |
| Hamburger buns | 4 | |
| Mozzarella slices | 8 | |
| Spinach | 2 cups | |
| Tomato | 1 large | sliced at camp so it does not weep |
Method
- At home, shake the balsamic, Worcestershire, 2 tbsp olive oil, cayenne, salt, and pepper into a zip bag with the mushroom caps. It rides in the cooler and marinates on the drive.
- In a second small jar, stir the mayonnaise with the garlic, lemon juice, paprika, remaining 2 tbsp olive oil, and a pinch of salt. Keep it cold.
- Build a charcoal bed or burn a fire down to coals and set the grate about four inches above them.
- Lay the caps gill side up so the marinade pools in them. Four minutes, then flip. Four more.
- Flip once more, drop two mozzarella slices on each cap, and tent loosely with foil until the cheese slumps.
- Toast the buns cut side down for thirty seconds. Spread the garlic mayo, stack two caps per bun, then tomato and a handful of spinach.
Portobellos work on a grate because they are already mostly water and structure. The balsamic and Worcestershire soak into that open sponge on the drive, so the seasoning goes all the way through instead of sitting on the surface. Two caps per bun is not overkill; one cap shrinks to about half its raw size once the moisture cooks off.
Gill side up first matters. The cap holds the marinade like a bowl and it reduces down into the mushroom rather than dripping into the coals and flaring. The aioli is just mayonnaise with garlic and acid stirred in, mixed at home so camp work is spreading and stacking. Everything here needs a cooler, so this is a first or second night meal, not a resupply dinner.
Packing
Marinade and mushrooms go in one doubled zip bag; the aioli in a small screw-top jar. Both live in the cooler. Buns ride on top of the food box or they arrive flat.
Variations
- No grate: cook the caps in a cast iron skillet over the coals, lid on for the cheese melt.
- Swap the buns for a bed of couscous if you would rather not carry bread.
https://www.lodgecastiron.com/blogs/recipe/grilled-portobello-mushroom-feast-burger