Nine ingredients and forty minutes, and most of that time is the filling rather than the sandwich.
Both vegetables are cooked to a specific end: the onion soft and lightly caramelised, the mushrooms browned until their moisture has evaporated.
Why This Recipe Works
- Twelve minutes on medium-low sweetens onion rather than just softening it.
- Raising the heat for the mushrooms drives their water off instead of stewing them.
- Dry filling is what keeps a griddled sandwich from going soggy inside.
- Cheese above and below the vegetables holds the filling together when it is cut.
- Young Gouda melts pale and stretches rather than turning oily.
Ingredient Notes
- Young Gouda
- Six ounces, sliced. Young rather than aged — it melts pale and stretches, which is what the cut sandwich shows.
- Cremini mushrooms
- Eight ounces, sliced and browned until their moisture is gone. Sliced rather than diced, and both facts are visible in the filling.
- Yellow onion
- One small one, thinly sliced and given a full twelve minutes on medium-low. Soft pale strands rather than deep-brown jam.
- Seeded sourdough
- Four thick slices. The seeded crust is what gives the finished sandwich its dark-golden textured surface.
How to Make It
Onion twelve minutes, soft and lightly caramelised
Cook onion in oil and butter over medium-low heat until soft and lightly caramelised, about 12 minutes.
Heat up, mushrooms browned dry
Raise heat, add sliced mushrooms, salt, pepper, and thyme, and brown until their moisture evaporates.
Gouda, filling, Gouda
Butter the outsides of the seeded sourdough. Layer Gouda, mushrooms, onion, and more Gouda inside.
Medium-low until the crust darkens and the Gouda stretches
Griddle over medium-low heat until the seeded crust is dark-golden and the Gouda stretches.
Extra mushrooms alongside, no meat and no sauce
Serve with a few extra browned mushrooms alongside if desired. Do not add meat or sauce.
The Filling Is Most of the Work
Forty minutes for a grilled cheese sounds excessive until you notice that the sandwich itself takes about six of them. The two vegetables are cooked to specific and different endpoints first, and both endpoints are about removing water.
Stage 1 of 4
The onion - low and slow, 12 minutes
Steps 1–1 of 5
1 small yellow onion, thinly sliced, in 1 tbsp of olive oil and 1 tbsp of butter over MEDIUM-LOW for about 12 MINUTES until SOFT AND LIGHTLY CARAMELISED. Lightly is the limit: you want soft PALE caramelised strands, not the dark jam a French-onion treatment would give. Twelve minutes on low sweetens; four minutes on high just softens and stays sharp.
- Onion twelve minutes, soft and lightly caramelisedCook onion in oil and butter over medium-low heat until soft and lightly caramelised, about 12 minutes.
Stage 2 of 4
The mushrooms - heat UP, and cooked dry
Steps 2–2 of 5
The heat RAISED, then 8 oz of sliced cremini with 1/2 tsp salt, 1/4 tsp pepper and 1 tsp thyme, browned UNTIL THEIR MOISTURE EVAPORATES. The opposite setting to the onion, in the same pan, for the opposite reason: mushrooms are mostly water and it has to leave. Any of it remaining goes into the bread later and steams the sandwich from the inside.
- Heat up, mushrooms browned dryRaise heat, add sliced mushrooms, salt, pepper, and thyme, and brown until their moisture evaporates.
Stage 3 of 4
Built cheese-filling-cheese
Steps 3–3 of 5
4 thick slices of SEEDED SOURDOUGH buttered on the OUTSIDES with 2 tbsp of softened butter, then layered Gouda, mushrooms, onion, and MORE GOUDA. 6 oz of YOUNG Gouda in total - young because it melts pale and stretches, which is both what the photograph shows and why the title's cheese and the white melt are not in conflict. Cheese on both sides of the vegetables is structural: it is what binds a loose filling so the cut sandwich holds.
- Gouda, filling, GoudaButter the outsides of the seeded sourdough. Layer Gouda, mushrooms, onion, and more Gouda inside.
Stage 4 of 4
Griddled slowly, two conditions at once
Steps 4–5 of 5
MEDIUM-LOW until the seeded crust is DARK-GOLDEN and the Gouda STRETCHES. Both have to happen together, and low heat is what buys the time - a seeded crust catches quickly, and 6 oz of cheese in a thick sandwich needs longer than the bread does. A few extra browned mushrooms may go alongside; step 5 rules out meat and sauce.
- Medium-low until the crust darkens and the Gouda stretchesGriddle over medium-low heat until the seeded crust is dark-golden and the Gouda stretches.
- Extra mushrooms alongside, no meat and no sauceServe with a few extra browned mushrooms alongside if desired. Do not add meat or sauce.
Success Tips
- Give the onion its twelve minutes; hurried onion is sharp rather than sweet.
- Raise the heat before the mushrooms go in, and let their water cook off completely.
- Griddle on medium-low so the seeded crust darkens as the Gouda melts.
Serving Ideas
Two sandwiches cut and stacked on white plates, the seeded crust dark-golden, the stretching pale Gouda holding browned mushrooms and soft onion, with thyme on top and a few extra mushrooms alongside.
Frequently Asked Questions
Why young Gouda rather than aged?
Young Gouda melts pale and stretches. Aged Gouda is drier and tends to separate rather than pull.
Why brown the mushrooms until dry?
Eight ounces of mushrooms hold a lot of water, and any of it left in the filling steams the bread from the inside.
How is this different from the pesto grilled cheese?
That one is mozzarella with a thick pesto layer on plain white bread. This is young Gouda with mushrooms and onion on seeded sourdough.
