Preheat the oven to 500°F (if using a baking sheet) or as high as it will go (if using a baking stone/steel; place the stone/steel in the oven before you start preheating).
If you are using fresh lima beans, bring a pot of water to a boil. Add the limas, blanch for 4 minutes, then immediately drain them in a colander in the sink. Run cold water over the limas to stop the cooking and lock in their bright green color. (If you're using thawed frozen limas, you can skip this step.)
Melt the butter in a medium skillet over medium-high heat. Add the onion and a small pinch of salt and cook, stirring frequently, until the onion just begins to caramelize, 5 to 8 minutes. Turn off the heat and stir in the lima beans. Set aside to cool slightly.
Stretch or roll out your dough to a 12-inch circle, then transfer it to an oiled baking sheet or a floured pizza peel (if using a baking stone/steel).
Top the dough with the onion-lima mixture, spreading it out evenly, and use any remaining butter in the skillet to brush the edges of the dough. Scatter the ham and blue cheese over the onion-lima mixture.
Transfer the pizza to the oven and bake until the crust is golden and the cheese has browned in spots, 8 to 10 minutes on the baking sheet, 6 to 8 minutes on the baking stone/steel.
Take the pizza out of the oven and sprinkle with parsley. Slice and serve.