This is an old fashioned American favorite for use as a preserve. See the USDA’s guidelines for home canning.
4 large lemons
1 large orange
Water as needed
Sugar as needed
Step 1. Remove the peel from the lemons and orange. Cut the peel into paper-thin julienne strips and combine with the sliced or chopped fruit. Discard seeds.
Step 2. Add one cup water for each cup pulp and peel. Let stand overnight.
Step 3. Boil the mixture until the peel is tender. Cool.
Step 4. Add one cup sugar for each cup of fruit and juice. Cook until the syrup gives a jelly test - two drops form on the edge of a metal spoon and drop off simultaneously. Stir occasionally. Pour into hot sterilized half-pint jars. Seal at once. Store for later use.