In a small saucepan, melt the unsalted butter over low heat. Once fully melted, remove from heat and allow to cool slightly.

In a medium bowl, whisk together the all-purpose flour, baking powder, and salt.

In a large mixing bowl, beat the two large eggs and granulated sugar together until pale and frothy, about 3-5 minutes. Stir in the vanilla extract and lemon zest.

Gently fold the dry ingredients into the egg mixture until just combined, then fold in the melted butter.

Preheat your oven to 375°F (190°C). Grease your madeleine pan with a little extra butter.

Spoon the batter into the prepared madeleine pan, filling each mold about 3/4 full.

Bake in the preheated oven for 10-12 minutes, or until the edges are golden.

In a microwave-safe bowl, combine the semi-sweet chocolate chips and coconut oil (if using). Microwave until smooth.

Once the madeleines are cool, dip one end into the melted chocolate and place on a parchment-lined baking sheet to set.

Serve your chocolate-dipped madeleines with tea or coffee or enjoy them as a treat on their own.