Tart Apel Prancis yang Mudah - Tarte Fine aux Pommes

Bahan-bahan (4 porsi)

• 1 square sheet butter puff pastry ((25cm / 10" square), barely thawed (Note 1))
• 5 tsp caster sugar (/ superfine sugar (sub regular / granulated))
• 2 large gala apples ((or 3 medium), peeled, cut in half, core removed, sliced 0.5cm / 0.2" thick (Note 2))
• 1 tbsp unsalted butter (, melted)
• Icing sugar / powdered sugar (, for dusting (optional))
• Vanilla ice cream ((not really optional!))