Here are 6 tips to balance the bitterness:
Sauté or Steam: Sautéeing or steaming greens helps the mature, tough leaves become tender and mild. Braising or blanching is even better for very tough, bitter greens since the bitter compounds leach into the water, and boiling softens tough-stemmed greens like kale. More delicate, younger bitter greens like baby arugula usually don't need to be pre-cooked - just seasoned right.
Salt: sodium chloride suppresses the perception of bitter flavors. I like to use a high quality sea salt, which adds a lot of flavor. You can also use other salty ingredients such as soy sauce.
Sour: Acidic ingredients can also be used to neutralize bitterness since the the bitterness in greens is attributed to pH basic alkaloids. Lemon juice squeezed over cooked or raw greens makes the flavors become brighter and reduces the bitterness. Vinegar also can be used to add acidity. Tomatoes are also a good choice, giving a touch of sourness but also a gentle sweetness.
Fat: Olive oil, rich cheeses such as parmigiano reggiano, dairy products, and pork products such as bacon and pancetta add comforting warmth to even the most astringent greens.
Sweet: A sweet balsamic vinegar reduction or a bit of honey can also be used to balance the bitter flavor. For example, escarole can be paired with golden raisins and pine nuts.
Spicy: Adding spicy chilies or hot sauces to greens will also counteract the bitterness in greens.
Caribbean Style Kale with Coconut Milk, Chilies, and Tomatoes
This recipe uses the 5 of the components above to balance the bitter flavors of the kale. The combination of the coconut milk, chilies, and tomatoes make a nice addition to other greens as well.
1 Tbsp olive oil
2 garlic cloves, minced
1/2 cup onion, chopped (such as Vidalia)
1-2 small red chilies, seeded and minced, such as Thai chilies
1 bunch of kale, chopped with tough stems removed
1/2 cup lite coconut milk
1 large tomato, chopped with the juices reserved
1/2 cup chopped green spring onions (optional)
Salt and pepper, to taste
Heat the olive oil over medium heat. Add the garlic, onions, and red chilies. Sauté until the chopped onion is soft and light brown. Add the kale and sauté for 2 minutes. Add the coconut milk and tomato, stir and let the kale mixture braise for 5-7 minutes. Add chopped green onions, salt, and pepper to taste.
Escarole alla Romana
The pan will be full with the fresh escarole, but the volume reduces quickly when cooked.