Pick through your dandelion greens and remove any leaves which are brown or discoloured. Chop them up into portions which are about 6 inches long (smaller dandelion greens will not need to be cut).
Remove any large tough roots, and any excess dirt. Next, carefully wash your dandelion greens. The best way to do this is to work with two large bowls. Fill each one with water and immerse your greens, a few handfuls at a time, into the first bowl. Place your hand into the water with the greens and shake it around, almost like the agitator of a washing machine would. After you do this for about 30 seconds, move the dandelion greens over to the next bowl which is also filled with water. Empty the first bowl, and refill with water.
Repeat until the water left behind when you transfer your dandelion greens, is crystal clear. Keep in mind that dandelion greens you pick yourself will likely be dirtier than those you buy at the supermarket.
Bring a large pot of water to a boil. Add salt to taste to the water (usually we add 1 teaspoon per 4 liters of water). Once the water has come to a boil, add your dandelion greens.
Cook, uncovered, over medium heat for approximately 15 – 25 minutes, until the dandelion are tender. Every 5 minutes or so, stir the greens around in the pot. Actual cooking time will depend on how tender your dandelion greens were to begin with.
Drain the cooking liquid. (You can reserve the cooking liquid to make a tea. See here) Right before you are planning to serve your dandelion greens with grilled bread, toss your greens with the lemon juice and olive oil. You can add salt at this point as well, if you desire. Note, the quantities of lemon juice, olive oil and salt are really up to your own taste.