Prepare the custard by combining the zest and juice of 1 orange and juice of 2 lemons—should be about 6 tablespoons juice in a small saucepan. Whisk in the sugar, salt, margarine and eggs and cook on medium heat for 2-3 minutes, whisking constantly so as not to scramble the eggs. Whisk in the corn starch for another minute or two until thickened and beginning to bubble. Remove from heat.

Meanwhile, wash, core, and halve your apples. Use a mandoline at 1/8 inch (ideal), or slice very, very thin slices of apple by hand. Cut each stack of sliced apples in half so that you have a half moon shape. Squeeze 1 lemon over the apples and toss gently. Set aside to soften slightly for about 10 minutes. If still very firm, place in microwave for 20 seconds.

Preheat oven to 350°F and line a baking sheet with parchment paper. Place tart shells on tray and fill shells halfway with reserved citrus curd. Set aside and prep apples.

Arrange 10-12 apple slices lengthwise in a straight line, overlapping each other. Starting at the end closest to you, roll up the apple slices in one constant motion. Carefully place rosette in the custard-filled tartlet. Spread out the leaves slightly and continue with remaining apples.

Once all the rosettes are formed, mix together the orange marmalade and water in a cup. Using a pastry brush, very gently dab the tops of the tartlets with the mixture to create a shiny glaze. Dust with cinnamon and bake for 25 minutes until edges are slightly golden and curled.

Serve warm.