Combine the milk, sugar, and yeast in a small bowl or measuring jug. Let stand until foamy, about 5 minutes.
In a large bowl, whisk the flour, garlic powder, and salt together.
Pour the milk mixture, along with the beaten egg, 2 tablespoons melted butter, and the thyme into the bowl with the flour. Mix until no dry patches remain.
Turn the dough onto a floured surface and knead until the dough is soft and smooth, about 3 minutes. Shape it into a ball, place it back in the bowl (or in your Dutch oven) and cover loosely with plastic wrap. Let rise in a warm place until doubled in size, 1 to 1 ½ hours.
Divide the dough into 8 even pieces and shape them into balls. Place the dough balls in a parchment-lined Dutch oven. Cover with plastic and let them rise until puffy, 45 to 60 minutes.
While the dough balls are rising, prepare hot coals or embers for cooking. You'll need 24 coals to begin cooking and they take about 15 minutes to be ready for use. They're ready when they are white all over.
Remove the plastic and cover the Dutch oven with its lid. Place 8 coals under the oven and 16 on the lid. Bake until the rolls are puffy and light golden brown, 30 to 35 minutes, replacing the coals as needed.
Uncover and brush the rolls with the remaining 1 tablespoon melted butter. Serve warm.