puff pastry with chard, red onion and swiss

My assistant Jose doesn't eat vegetables. A chef that doesn't eat vegetables. Scary. So one day when he came to me and said, I have a recipe for asparagus that I think you will like, I was shocked. He got it from a cookbook (not sure which one) and it consisted of three ingredients. Puff pastry, gruyere, and grilled asparagus layered together as a tart. I should have known. Cheese, butter, white flour and a smidge of vegetables. Then I thought about it. Cheese- awesome. Puff pastry- awesome. Veggies- totally sweet. We made it, ate it, fell in love and are still serving it. So I decided to morph the recipe a little bit with some different flavors and a little more cheese and make it for dinner. I will also make it in smaller portions for the next time we invite people over. Plus, it will work with almost any veggies and cheeses. Oh, and its RIDICULOUSLY easy.

Ingredients:
1/2 sheet of Dufour Puff Pastry (This is THE BEST Puff Pastry, a little more expensive, but sooooo worth it).
2 medium yellow onions, sliced in half moons
1 bunch red chard, roughly chopped
4 slices swiss cheese
1 Tbsp olive oil
1 Tbsp canola oil
salt and pepper to taste

Preheat your oven to 375 degrees. Oil a cookie sheet, or the foil on top of one and place your puff pastry on it. Toss it into the oven and bake for 30 to 35 minutes until it starts to get golden brown. While its baking put a frying pan on medium heat, add the oil and onions and stir occasionally until caramelized, about 20 minutes. Add the chard and season. Continue to stir until the chard is wilted, about 5 to 7 minutes. By now your pastry is baked. Layer the chard and onion mixture on top, cover with cheese and return to the oven. Bake until cheese is melted, about 7 to 8 minutes. Now get your grub on.