Melt butter in a small saucepan over medium heat, swirling occasionally until it turns golden brown and smells nutty, about 5-7 minutes. Add chopped thyme and stir for 30 seconds. Pour into a shallow dish and refrigerate until solid but still slightly soft, about 25 minutes.

Preheat oven to 220°C (425°F) and line a baking sheet with parchment paper.

In a large bowl, whisk together flour, baking powder, salt, and sugar.

Cut the chilled brown butter into small cubes and add to the flour mixture. Use a pastry cutter or your fingertips to work the butter into the flour until the mixture resembles coarse crumbs with some pea-sized pieces remaining.

Make a well in the center and pour in cold buttermilk. Stir gently with a fork until just combined, being careful not to overwork the dough.

Turn dough onto a lightly floured surface and pat into a rectangle about 2cm thick. Fold in thirds like a letter, then pat out again. Repeat this folding process twice more for flaky layers.

Pat dough to 2.5cm thickness and cut into rounds using a 6cm biscuit cutter, pressing straight down without twisting. Gather scraps gently and repeat.

Place biscuits on prepared baking sheet, leaving 3cm between each. Brush tops with beaten egg and sprinkle with flaky sea salt.

Bake for 14-16 minutes until golden brown on top and cooked through.

Remove from oven and immediately drizzle with honey while still warm. Serve within 30 minutes for best texture.