I agree that roasting veggies can do wonders for them! Pretty much any vegetable is great roast. My usual approach is to chop it into big pieces (if necessary), toss it with a bit of olive oil, minced garlic, kosher salt, and coarsely ground pepper, then roast at maybe 400 degrees until as tender as you want. So good. Broccoli, carrots, beets, squash, brussels sprouts, cauliflower, zucchini, mushrooms, even tomatoes (leave them whole if they're cherry tomatoes or cut them in half and put them cut side up if they're bigger) are great that way. Grilled veggies are amazing as well, I do the same thing with the oil, salt, and pepper and just toss them on the grill. The ONLY way I like onions that haven't been cooked until completely soft is when they're grilled, specifically red onions. Yummy
My husband was skeptical of how wonderful zucchini, red onion, bell pepper, and mushrooms could be until he tried them grilled, now he loves them.
As for the kale, my husband and I actually like it in salads completely raw and un-tenderized, but that may be slightly odd. Regardless, one of our favorite recipes is as follows. It tastes wonderful and the kale is not tough at all because the hot dressing breaks down the toughness (for lack of a better term) and then you massage the dressing in, which helps even more. You can tone down the vinegar if you don't like tart, but we think it's perfect as is.
-1 bunch kale, washed, dried with paper towels, stalk discarded, and leaves chopped into bite size pieces (or you can just buy a 10 oz bag of washed, chopped kale- I do that too and it works great)
-1/4 C extra virgin olive oil
-2 cloves minced garlic
-1/4 C apple cider vinegar
-1/2 t salt (or to taste, you might want less)
-1/3 C grated parmesan cheese (not the green can kind)
Place the kale in a large bowl. Pour the olive oil into a small skillet and add the garlic. Cook over medium until garlic turns light golden, then stir in vinegar. Let it simmer for maybe 30 seconds to a minute, then remove from the heat and pour it over the kale. Use tongs to toss the salad for a minute, until it's cool enough to handle. Then use your hands to massage the dressing into the kale for a couple of minutes. Add the parmesan and toss to distribute it, then add salt to taste. You can either serve it as is or refrigerate it until cold. It keeps well in the fridge for at least a day, but has never lasted longer than that because we really like it.