Ina Garten-Inspired Spinach Gratin
A watery spinach gratin did not fail in the oven. It failed at the sink.
Frozen spinach is roughly half water by weight, and thawing releases almost none of it. A kilo of thawed spinach will give up two cupfuls if you actually squeeze it — and if you do not, that liquid has nowhere to go but into the cream sauce, where it thins a béchamel you spent ten minutes building.
Wring it in a tea towel, in handfuls, until nothing more runs out. The spinach should come apart in dry clumps.
Jump to the recipe ↓Ina Garten-Inspired Spinach Gratin
Serves 8 · Side
- Prep
- 20 min
- Cook
- 30 min
- Total
- 50 min
Moderate7 steps, 11 ingredients
Ingredients
- 1.4 kg frozen chopped spinach, thawed and wrung dry
- 4 tbsp butter
- 2 onions, finely chopped
- 3 tbsp plain flour
- 300 ml whole milk, warmed
- 150 ml double cream
- 1/4 tsp grated nutmeg
- 1 tsp kosher salt
- 1/2 tsp black pepper
- 100 g Gruyère, grated
- 50 g Parmesan, grated
Method
- Heat the oven to 200°C (180°C fan).
- Wring the spinach dry in a tea towel, in handfuls. Do not skip this.
- Melt the butter and cook the onions over medium-low, until soft and sweet.15 minutes
- Stir in the flour and cook , so the sauce does not taste of raw flour.2 minutes
- Whisk in the warm milk and cream. Simmer until it coats a spoon.
- Off the heat, add nutmeg, salt, pepper, the spinach and the Gruyère.
- Spread in a baking dish, scatter the Parmesan over, and bake until bubbling and browned at the edges.20 minutes
Cook the onion far longer than looks necessary
Fifteen minutes in butter over medium-low, until it collapses and sweetens. Raw or barely-softened onion stays sharp under cream, and the gratin ends up tasting of onion rather than of spinach.
Nutmeg is doing structural work here
A dairy sauce with no nutmeg tastes flat in a way people usually try to fix with more salt. A few rasps off a whole nutmeg is enough — grated to order, because pre-ground loses its volatile oils within months.
The two cheeses are not interchangeable
Gruyère goes into the sauce because it melts smoothly and carries a nutty savouriness through the whole dish. Parmesan goes on top because it browns and crisps rather than pooling into fat. Swapping them gives you a greasy top and a bland middle.
Storing
Assemble up to two days ahead and refrigerate unbaked; add 10 minutes to the bake from cold. Once baked it reheats well at 180°C, covered, though the crust softens.
Questions people ask
Can I use fresh spinach?
Yes — you need about 2.7 kg, wilted in batches, then squeezed exactly the same way. The volume loss is startling the first time.
Why is mine watery?
The spinach was not wrung out hard enough. Thawing and draining in a sieve is not the same as squeezing.
Can I make it ahead?
Yes. Assemble unbaked, refrigerate up to two days, and bake from cold with an extra 10 minutes.
Do I have to use Gruyère?
Comté or a mature Emmental behave the same way. Cheddar splits into oil under a cream sauce and is the usual cause of a greasy gratin.
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