Using a sharp paring knife, slice off ends of grapefruit. Following curve of fruit, cut away outermost peel, leaving behind most of white pith. Slice peel lengthwise into ΒΌ-inch-thick strips.
In a medium saucepan, heat peel and water to cover over medium heat until tender, about 10 minutes. Remove peel using a slotted spoon; set aside.
In a medium saucepan, heat 2 cups sugar and 1 cup water over medium heat until sugar is dissolved. Add peel, and bring to a boil. Reduce heat, and simmer until peel becomes translucent, about 10 minutes. Remove peel, and toss with remaining 1 cup sugar. Let dry on a wire rack. Store in an airtight container for up one month.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/citrus-tart/