1 1/2 pounds yellow onions, preferably a sweet variety, thinly sliced
About 1/2 cup olive oil
6 cloves garlic, slivered
1 pound chard, thick ribs removed, cut into 1-inch-wide ribbons
10 ounces day-old chewy artisan bread, cut into rough 1-inch cubes
2 cups good-quality chicken broth
About 2 loosely packed cups good-quality Swiss Gruyère
To prepare the onions:
Place the onions in a large, deep saucepan or Dutch oven, and drizzle and toss with about ¼ cup olive oil. Set over medium-high heat, and shaking the pan occasionally, cook until the bottom layer of onions is golden on the edges, about 3 minutes. Stir, and repeat. Once the second layer of onions has colored, reduce the heat to low, and stir in the garlic and a few pinches of salt. Let cook, stirring occasionally, until the onions are pale amber and tender but not mushy, another 20 minutes or so. If at any point the onions look as though they’re drying out, cover the pan to trap in moisture.
Preheat the oven to 325 degrees Fahrenheit.
To prepare the chard:
Place handfuls of chard in a large sauté pan or skillet, drizzle with olive oil, and sprinkle with water and a few pinches of salt. Set the pan over medium heat until the bottom layer of leaves begins to cook; then reduce the heat and stir and fold the leaves until they are just wilted, 2-4 minutes. The leaves should be bright green and their white veins quite pliable. Set aside.
To prepare the bread:
Using your hands, toss and massage the cubed bread with 2 or 3 Tbs olive oil, ¼ cup of the broth, and a few pinches of salt.
To build the panade:
Using a flameproof 2-quart soufflé dish or deep, enameled cast-iron pan, assemble the panade in layers. Start with a good smear of onions, followed by a loose scattering of bread cubes, a thin layer of onions, a blanked of chard, and a handful of cheese. Repeat, continuing until all ingredients are incorporated and the dish is full. Aim for 2 to 3 layers of each component, but make sure that the top is a mosaic of all the ingredients. Don’t worry if the layers are a bit uneven, or if you have to pack them down a bit—this is meant to be rustic.
Bring the remaining 1 ¾ cups broth and 2 cups water to a simmer in a medium saucepan. Pour the warm liquid slowly, in doses, over the assembled panade, drizzling it down the sides of the dish. The liquid should come up nearly to the top of the layered ingredients.
Set the dish over low heat on the stovetop, and bring its liquid to a simmer, looking for bubbles around the edges. Cover the top of the dish with parchment paper, then very loosely cover the top again with aluminum foil. Place the panade on a baking sheet to catch drips, slide it into the oven, and bake it until hot and bubbly, about 1 to 1 ½ hours. The top should be pale golden and a bit darker on the edges.
Uncover the panade, raise the oven temperature to 375 degrees Fahrenheit, and leave until for another 10-20 minutes, until the top is golden brown. Remove it from the oven, allow it to settle for a minute or two, and then serve.