Directions:

Wash and dry the oranges and lemons. Remove the layer of zest from all the fruit. Use a sharp swivel peeler to cut off the outer layer of peel in thin sheets, then sliver on a cutting board. Cover the slivered peel with cold water in a saucepan, bring to a boil and simmer 5 minutes. Drain, add fresh water and repeat this twice but reserve the liquid as well as the peel after the third simmering. While the peel cooks, squeeze and strain the juice from oranges and lemons. If you don't have 3 cups of juice, pour in enough additional orange juice to make up that amount. Combine the peel, 1 cup of the cooking liquid, the combined orange and lemon juice, pineapple juice, sugar and the dab of butter to prevent boiling over in a very large stainless stell or other non-reactive pan. Bring to a boil, stirring to dissolve sugar, then boil at a moderate rate, stirring occasionally, for 10-15 minutes, until syrup has thickened a little. It will thicken more after cooling. Taste and add a little more lemon juice, if you like. Pour sauce into a sterilized jar or jars, let it cool, then cover and refrigerate. It will keep for months. At serving time, add about 2 tablespoons orange-flavored liqueur or kirsch per cup of syrup to use as a dessert sauce over crepes, ice cream or cake. Use without liqueur for fancy French toast or waffles. Drizzle over fresh strawberries and blueberries, in season.