Preheat the oven to 400 Degrees.
1. Peel and pit the Diamond Bright nectarines then cut them into even slices. Place them in a large mixing bowl and coat them with the juice of 1 lemon.
2. Combine the sugars, flour, salt and cinnamon. Sprinkle this mixture over the nectarines and toss to combine.
3. Unwrap the pie crusts. Place them on a lightly floured surface, one at a time, and gently roll each one to extend it about a half-inch all around.
4. Place each crust on a parchment-lined pan. Brush each crust with 2 tablespoons soft butter, leaving about 1 inch all around with no butter.
5. Sprinkle ½-cup bread crumbs evenly over the butter on each crust. Divide the nectarines between the two tarts. Dot the nectarines on each tart with ½-cup butter.
6. Fold the edges of the pastry over the edge of the nectarine slices, crimping the excess pastry to form a rustic tart shape.
7. Bake until the nectarines are tender and the crust is brown 30-40 minutes.
8. Remove from the oven. Melt the jelly and brush it over the nectarines.
9. Serve warm or at room temperature with a scoop of ice cream.