1 1/4 c. graham cracker crumbs
1/4 c. sugar
1/3 c. melted butter
2 (15 or 16 oz.) containers ricotta cheese
1 can sweetened condensed milk
4 eggs
2 tbsp. plus 1 tsp. orange flavored liqueur
2 tbsp. flour
2 tsp. vanilla
1/3 c. orange marmalade
Fresh orange slice or orange segments

Combine crumbs, sugar and butter, press firmly in bottom of 9 inch spring form pan. In large mixer bowl combine cheese, sweetened condensed milk, eggs, 2 tablespoons liqueur, flour and vanilla; mix well. Pour into prepared pan. Bake in 325 degree oven for 1 hour and 20 minutes or until set. Cool. Heat remaining 1 teaspoon liqueur with marmalade; spread about 3/4 on top of cheesecake. Top with orange slices then remaining marmalade mixture. Chill thoroughly.