Preheat your oven to 350°F (175°C) and grease an 8-inch round cake pan.

In a saucepan over medium heat, melt the unsalted butter, stirring until golden brown and nutty (about 5 minutes). Allow it to cool slightly.

In a large mixing bowl, whisk together the browned butter, granulated sugar, eggs, lemon zest, and juice until smooth.

In another bowl, combine the flour, baking powder, and thyme leaves. Gradually fold the dry mixture into the wet ingredients until just combined.

Pour the batter into the prepared pan and bake for 30–35 minutes or until a toothpick inserted in the center comes out clean.

Let cool completely before drizzling with a glaze made from powdered sugar mixed with leftover lemon juice.