Melt the butter in a medium skillet over medium heat. Add the shallots and a pinch of salt and cook until soft and translucent, about 4 minutes.
Stir in the peas and 1/2 teaspoon salt and cook until the peas are soft but still bright green, 2 to 3 minutes. Add the lemon juice and toss. Remove from heat and stir in the Parmesan and a generous pinch of black pepper. Serve hot.