Tomato Jam

3 pounds (about 6 large) ripe tomatoes
1 lemon, sliced thin
3 cups granulated sugar

Skin, core and quarter tomatoes. Remove seeds. Put tomatoes in saucepan and bring to boil. Simmer, uncovered, for 8-10 minutes. This should yield about 3 cups pulp (adjust other ingredients accordingly if it varies from this). Return tomatoes to pan. Stir in lemon slices and sugar. Bring to boil and continue cooking, stirring constantly until jam thickens. Pour into jars and seal.