Slice the peaches into chunks, and place in a blender with the peach nectar, lemon juice, and salt. Blend until smooth. Set aside.
In a medium bowl, beat the sugar into the eggs until they are thickened and pale yellow. Beat in the flour. Set aside.
Bring the milk to a simmer in a heavy medium saucepan. Slowly beat the hot milk into the egg and sugar mixture. Pour the entire mixture back into the pan, and place over low heat. Stir constantly until the custard thickens slightly. Be careful not to let the mixture boil, or the eggs will scramble. Remove from heat, and pour the hot custard through a strainer into a large clean bowl. Pour the peach puree through the strainer into the same bowl. Allow the custard to cool slightly, and mix in the cream. Cover and refrigerate until cold or overnight.
Stir the chilled custard, then freeze in your ice cream maker according to the manufacturer’s directions. When finished, the ice cream will be soft but ready to eat. For firmer ice cream, transfer to a freezer-safe container and freeze at least 2 hours.