for Swiss Chard Gratin:
* 1 kilo (2.2 pounds) Swiss chard (blettes in French)
* olive oil
* 1 medium yellow onion, thinly sliced
* 240 ml (1 cup) non-dairy béchamel (store-bought or from recipe below)
* 1 egg (optional)
* 30 grams (1 ounce) freshly grated comté (substitute the gratable cheese of your choice or some nutritional yeast)
* 2 tablespoons oat bran (substitute bran from another grain, or dried breadcrumbs)
* salt, pepper

for Vegan Béchamel:
* 4 teaspoons vegetable oil
* 2 tablespoons flour
* 240 ml (1 cup) plain oat milk, or other non-dairy milk, cold or at room temperature
* salt, pepper, nutmeg