Step 1

Make the super green purée:

Step 2

Preheat oven to 400 F and bring a large saucepan of salted water to a boil. Prepare a bowl of ice water on the side.

Step 3

Place the butter in a small saucepan and brown it over medium heat. Add the sliced shallots and garlic, and cook until tender.

Step 4

Pour the heavy cream over the shallot mixture and simmer until reduced by half.

Step 5

Boil the spinach leaves for 2 minutes, or until very tender, then chill in the ice water. Strain and squeeze the leaves dry.

Step 6

Transfer to a blender with the hot cream mixture. Purée on high speed until very smooth, season with salt and pepper and pass through a fine-mesh sieve. If not using immediately, chill in a bowl placed over ice.

Step 7

To assemble:

Step 8

In a large sauté pan over medium heat, warm the olive oil. Add the spinach and season with salt and pepper.

Step 9

Once wilted, add the super green purée until the spinach is creamy and transfer into a baking dish.

Step 10

Top with the Gruyère cheese and bake until melted.