Heat the broth to very hot in a medium saucepan. Cover and set aside to keep warm.
In a large, deep, dry skillet, pan-fry prosciutto 1 minute per side and set aside on a plate.
In the same pan, melt 2 tablespoons of the butter with the oil over medium heat. Add the onion and carrot and a pinch of salt.
Cook, stirring often, until nearly tender, 6 to 8 minutes. Add the garlic and cook, stirring, until fragrant. Add the rice; cook, stirring, for 2 minutes until hot and well coated. Reduce the heat.
Being careful as the pan is very hot, add about ½ cup of the warm broth. Cook, stirring, until it’s nearly absorbed. Keeping the rice at a steady simmer, continue adding all but ¼ cup of the broth, stirring until the rice is creamy and just tender (but still al dente) and there is some liquid left, about 15 minutes.
At the last minute, heat the remaining 1 tablespoon butter in a medium skillet. Add the peas, the ¼ cup broth (or some water), and season with salt. Cover and cook until peas are just tender, 3 to 5 minutes. Stir into the rice with any remaining liquid.
Remove the risotto from the heat. Stir in the crisped prosciutto chips, scallions, and Parmesan.
Season well with salt and pepper and serve right away with more Parmesan.