In a stand mixer bowl, mix the dry ingredients: flour, active dry yeast, sugar, and salt. Make sure they're well mixed.
Add the wet ingredients: warm milk, melted butter, and eggs. Use the dough hook to knead until the dough is smooth and elastic, about 7 minutes.
Gently mix in chocolate chips or your favorite chocolate filling. Make sure they're spread out evenly in the dough.
Cover the dough and let it rise in a warm spot for 1.5 to 2 hours. It should double in size.
Punch down the dough to get rid of air bubbles. Then, divide it into 20 equal parts. Shape each part into a ball.
Place the dough balls on parchment-lined baking sheets, leaving some space between them. Cover and let them rise for another 60 minutes.
Preheat your oven to 350°F (175°C). Bake the buns for 15 to 20 minutes, until they're golden brown.
Take the buns out of the oven and let them cool on a wire rack. You can add a chocolate filling or spread before serving.