Peel and thinly slice the shallot. Cut the nectarines into ½-inch pieces. In a 2-quart sauce pot, melt the butter over medium heat. Add half the shallots, season with salt, and cook until beginning to soften, about 2 minutes. Add the nectarines and cook until they begin to release some of their juice, about 2 minutes. Stir in the mostarda mix, ½ cup water and the Urfa Biber chile, if using. Bring to a boil, reduce to a simmer, and cook, stirring, until the mixture thickens and the nectarines begin to fall apart, about 20 minutes.

• While the mostarda cooks,

• Prepare the sausages.

In a 12-inch frying pan or grill pan over medium-high heat, warm 1 tablespoon oil until hot but not smoking. Add the sausages to the hot pan and cook until well browned, about 6 minutes on each side. Transfer to a plate to rest.

• While the sausage cooks,

• Mince the garlic.
• Wash and coarsely chop the mustard greens.

In the same pan used to cook the sausages, add 1 teaspoon oil. Add the garlic and the remaining shallots and cook until beginning to soften, about 2 minutes. Add the mustard greens, season with salt and pepper and cook until just wilted, about 3 minutes.

Put one sausage on each serving plate along with some of the mustard greens. Serve the nectarine mostarda on the side.

These sausages take beautifully to grilling, just be sure to let them come to to room temperature first. They'll cook more quickly and evenly that way. Medium to low heat is best for these, so move them off to the side if your coals are very hot. You can also grill the greens directly on the grate or in a frying pan set over the coals.