Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper. Remove the Omaha Steaks Apple Tartlets from their packaging and place on the prepared baking sheet, leaving about 2 inches between each tartlet. Allow the tartlets to thaw slightly at room temperature for about 10 minutes while preparing the apple filling.

Peel the Granny Smith apples, removing all skin. Core the apples and cut them into thin, uniform slices (about ⅛-inch thick). Place the apple slices in a mixing bowl. Add the granulated sugar, ground cinnamon, and lemon juice to the bowl. Gently toss everything together until the apple slices are evenly coated with the sugar-cinnamon mixture.

Carefully arrange the apple slices on top of each tartlet in a decorative pattern. You can create a simple overlapping circular pattern or a more complex rose design by starting from the outside and working inward. Add any extra sugar-cinnamon mixture from the bowl by drizzling it over the arranged apples.

Crack the egg into a small bowl and beat it thoroughly with a fork or small whisk. Using a pastry brush, gently brush the edges of each tartlet with the beaten egg. This will give the crust a beautiful golden color and slight shine when baked.

Place the baking sheet with the assembled tartlets into the preheated oven. Bake for 15-20 minutes, until the crust turns golden brown and the apples become tender. For even browning, rotate the baking sheet halfway through the baking time.

Once baked, remove the tartlets from the oven and allow them to cool on the baking sheet for 5 minutes. Transfer to a cooling rack if you prefer a crisper bottom crust. Serve warm with your choice of accompaniments.