- 1 1/2 cups water, divided
- 1 blood orange or regular orange, thinly sliced with peel into rounds, seeded if necessary
- 2 1/2 tablespoons fresh lemon juice
Combine 1 cup sugar, 1 cup water, and orange slices in heavy medium saucepan. Bring to simmer over medium heat, stirring until sugar dissolves. Reduce heat to low; cook until orange peel is tender, stirring occasionally, about 30 minutes. Pour into strainer set over medium bowl. Chop orange slices and reserve; discard syrup.
Combine remaining 1 cup sugar, 1/2 cup water, and lemon juice in another heavy medium saucepan. Add chopped orange. Reduce heat to low; cook until orange is very tender and rind is translucent, about 30 minutes longer. Mix in Campari. Transfer marmalade to small bowl and cool. DO AHEAD Can be made 1 week ahead. Cover and chill.