Make the crêpe batter

• Whisk the flour, sugar, eggs, milk and water together in a bowl.
• Stir in the melted butter until the batter is smooth.
• Let the batter rest.

Cook the crêpes

• Heat a lightly buttered frying pan over medium heat.
• Pour a thin layer of batter and cook each crêpe until golden on both sides.
• Repeat with the remaining batter and set the crêpes aside.

Start the citrus marmalade

• Combine the sugar, water, lemon zest and juice, and orange zest and juice in a saucepan.
• Cook over low heat, stirring occasionally.

Enrich the marmalade

• Add the egg yolks one by one, stirring constantly.
• Stir in the butter until fully melted and incorporated.

Cool the marmalade

• Let the marmalade cool until creamy and spreadable.

Assemble the mille crêpes

• Stack the crêpes, spreading marmalade between each layer.
• Finish with a layer of marmalade on top and serve.