Bitter Seville Orange and Lemon Marmalade

This marmalade is based on a traditional English recipe that has evolved in my kitchen over the years. I add it to cakes, puddings, creams, breads, and sauces, both sweet and savory. I make lots of it every year to use up our abundant supply of bitter oranges as well as lemons from our old, very productive lemon trees. Traditionally in Greece citrus peel is zested, cut into segments, rolled and coiled on a thread, then cooked in syrup to make bitter orange or lemon preserves, called karo