If you haven't tried micro greens, they are a great introduction to indoor gardening and gardening in general. I'd say they are equivalent to growing sprouts in the amount of food they produce, only much easier. If you grow enough you can make salads out of them. They come in mild and spicy mixes as well as singles (like mustard seed). I like mixing the mild and spicy. I could see combining the mild with a pack of mustard or arugula micro greens if you really like those flavors. You could also combine them with a red or purple variety to add some color. I use them to enhance salads and other dishes (again, just like sprouts).
I threw together the first batch and stuck them in the sunroom. This time of year it's a little too hot and sunny, so they got kind of leggy. This is the first batch at 3 weeks growth ...
It was cooler by the time I did the second batch. I also made sure they got a little shade in the afternoon. They look much better (at 2 weeks growth) ...
You can see how I grow them from the picture. I punch holes in the top tray before filling it with dirt. I keep it in a second tray and always water from the bottom by filling the second tray with 1/4" of water and replacing the top tray. The only exception is when I mist the seeds after they are first planted until they sprout (2-3 days). When it's cold, I use a heat mat or move them into a warmer room at night.
They are cut-and-come-again plants like lots of other greens. So easy.
I buy mixes from Johnny's and High Mowing. HM is cheaper but Johnny's mix is a little nicer/more attractive. Johnny's has more varieties if you really get into growing them. I'm cheap, though, and buy most of mine from HM.