Swiss Chard is one of my favorite greens!!!!
It's a great "cut-&-come-again" crop, & can be cut when just a few inches tall & used raw in salads or stirfries.
For older mature Swiss Chard, this is my favorite way of preparing it:
Sauteed Swiss Chard
1 bunch of Swiss Chard - any type
Water
Extra Virgin Olive Oil
3-4 garlic cloves, peeled
Dash of crushed red pepper flakes
Grated Parmesan Cheese (optional)
Italian Seasoned Bread Crumbs (optional)
Fill a pot large enough to hold the chard with water & bring to a boil.
Meanwhile, separate the chard leaves from the stems. Trim & discard the stem ends & cut the stems into 1"-2" pieces depending on stem thickness. Roughly chop/slice up the leaves, keeping them separate from the stem pieces. When the water reaches a boil, add the stems & cook for around 5 minutes. Then add the leaves to the pot as well & continue cooking for another 5 minutes. Drain in a colander.
Heat some extra-virgin olive oil in a skillet. Smash the peeled garlic cloves with the side of a large knife, sprinkle them with salt & roughly chop (the salt will keep the garlic from flying around your cutting board as you mince it). Add the drained chard, minced garlic, & crushed red pepper flakes to taste & stir until heated thru.
Sprinkle with grated Parmesan &/or Italian Seasoned Breadcrumbs if desired, stir again, & serve.
The above is my own recipe. I have others, but I'm not sure of their source, so I don't think I can post them here.