Preheat oven to 425°F and set an oven rack to the middle position. Line a baking sheet with parchment paper and set aside.

Add flours, sea salt, thyme and baking powder to a large bowl, whisking to combine. Add the butter to the bowl, and, using your fingers, work the butter into the dry ingredients until it resembles coarse meal. Stir in the gouda, then add the milk and stir until just combined.

Scrape dough out onto a lightly floured work surface, and knead 4 to 5 times, until it just holds its shape. Using a rolling pin, roll dough until 3/4 inch thick. Cut out 2 1/2-inch rounds with a cookie or biscuit cutter. Reroll and cut scraps as needed. Place biscuits on the prepared baking sheet at least 1 inch apart. Brush tops with melted butter, then sprinkle evenly with caraway seeds.

Bake biscuits until golden and cooked through (11 - 13 minutes). Let cool for just a moment before enjoying. Store any leftover biscuits covered at room temperature for up to several days.