The Southern mustard greens in my community garden plot have been so productive that I almost can't keep up...almost.
For the harvest pictured above, I made a frittata. After giving them a 20-minute soak in a sink full of water to wash and refresh them, I briefly blanched them as whole leaves in a big pot of lightly-salted water. Once they started to wilt (it only takes a minute), I removed the leaves from the boiling water and ran them under cool water to halt the cooking, making them cool enough to touch. I squeezed the excess water out, chopped them on my cutting board, and set them in a container in the fridge. It was Thursday morning and I had to leave for work; the rest would wait for Saturday for brunch at home.
On Saturday morning, I warmed about a cup of the prepared greens in my biggest non-stick pan, which I had already lightly coated with olive oil. You could add other ingredients here if you wanted to, as fritattas are great for using up leftovers: diced baked potato, cooked chickpeas, and/or cooked ham would be lovely as would fresh herbs. Just be sure to resist the urge to pack it full of goodness, as you want a relatively-thin layer of filling. There needs to be space for the egg to intermingle and coagulate around your ingredients or the frittata will not set properly.
Once the greens started to sizzle and become fragrant (medium heat), I poured 6 beaten eggs all over them and reached for the feta cheese, which I crumbled on top. When the eggs started to set around the edges, I moved the entire contraption to under the broiler to finish the cooking, making it brown and bubbly on top.
Allow the frittata to cool for a few minutes before cutting it into wedges as you would a pizza. Top with hot sauce according to your taste and enjoy.