Take the pie crust from the refrigerator and allow it to come to room temperature before using. See package directions for time.
Preheat the oven to 400 degrees. Line a baking sheet with parchment paper. Unroll the pie crust onto the prepared baking sheet. Set aside.
Cut the apple in half, then cut into thin slices.
In a small bowl, combine 2 tablespoons of sugar (save the rest of the sugar) with the flour, and stir well. Sprinkle over the pie crust.
Arrange the apple slices onto the pie crust, starting 2-3 inches from the edge, then slightly overlapping. Repeat a second layer in the middle.
Bring the edges of the pie crust up, to meet the apples, and cover the edges just slightly. Melt the butter, and brush it over the apples with a silicone brush or pastry brush. Then sprinkle the remaining sugar over the apples.
Place the baking sheet on the center rack in the oven for 25-30 minutes, or until the apples are tender, and slightly golden. Once the tart is removed from the oven, melt the jelly in a small bowl for about 30 seconds in the microwave, then brush over the apples. Serve warm, or allow to cool before serving.