Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

On a floured surface, roll out two sheets of puff pastry to a 10x14-inch rectangle, then transfer to baking sheet.

Bake the tart shell for 12-15 minutes until golden brown, gently pressing down any puffed areas.

In a bowl, whisk together the eggs, then mix in Greek yogurt, garlic, salt, and cheddar cheese until smooth.

Spread the filling evenly into the baked pastry shell, filling just below the scored edges.

Melt butter in a skillet, sauté asparagus for 2 minutes, then add diced ham and cook for an additional minute.

Spread the sautéed asparagus and ham mixture over the filling evenly.

Whisk together an egg with a splash of water and brush the mixture onto the edges of the pastry crust.

Return the tart to the oven and bake for another 10-12 minutes until filling is set and crust is golden.

Let cool slightly, then sprinkle with fresh thyme and serve warm.