Warm the milk in a small saucepan over low heat until steaming but not boiling, about 2 minutes.

Remove from the heat, stir in the dried lavender, and steep for 5 minutes.

Pour through a fine-mesh sieve, pressing the lavender firmly to extract all the liquid. Discard the buds and set the infused milk aside to cool slightly.

Heat the oven to 170 C / 340 F. Grease a 9x5 inch loaf pan and line with parchment paper, leaving an overhang on both long sides.

Whisk the flour, baking powder, and salt together in a large mixing bowl.

In a separate bowl or large jug, whisk the melted butter, honey, and sugar until combined, about 1 minute.

Add the eggs one at a time to the butter-honey mixture, whisking after each addition until smooth.

Whisk in the sour cream, vanilla extract, and the cooled lavender milk until the wet mixture is uniform.

Pour the wet mixture into the flour bowl and fold gently with a spatula until just combined - stop as soon as no dry streaks remain.

Pour the batter into the prepared loaf pan and smooth the top with a spatula.

Bake on the center rack for 50 to 55 minutes, until a skewer inserted in the center comes out with only a few moist crumbs. Tent loosely with foil after 30 minutes if the top is browning too quickly.

Remove from the oven. If using the glaze, brush the surface immediately with warmed honey for a glossy finish.

Cool in the pan for 10 minutes, then lift out using the parchment overhang and transfer to a wire rack. Cool for at least 30 minutes before slicing.