Step 1

Preheat the oven to 200°F (100°C). Line 3 baking sheets with parchment paper and set aside.

Step 2

In a large mixing bowl, using a stand or handheld mixer fitted with a whisk attachment, combine water, sugar, and yeast and stir to combine. Let sit for about 10 minutes until it starts to get foamy on the surface.

Step 3

Add the egg, buttermilk, 3 tbsp melted butter, salt and vanilla and whisk to combine. Replace the whisk attachment and attach a dough hook. Add 3 + 1/2 cups of flour and stir on medium-low speed until the dough comes together. The dough should be slightly sticky to touch but shouldn't stick to the bowl anymore. If it does stick to the sides of the bowl add 1 tbsp of flour at a time until it doesn't stick to the bowl anymore. Then turn on medium speed and knead for about 5 minutes. Transfer the dough to a lightly greased (brush a few drops of oil in a bowl or use a non-stick spray) heatproof bowl. Turn off the preheated oven and place bowl in the oven to rise for about 15 minutes. Leave the oven door ajar.

Step 4

Remove the bowl from the oven and preheat again to 200°F (100°C).

Step 5

On a lightly floured surface roll the dough out into a rectangle or square, about 1/4 inch (0.6 cm) thick and cut 2-inch (5x5cm) squares with a pizza cutter or knife. Place on the prepared baking sheets. Turn off the preheated oven and place all 3 baking sheets in the oven to rise for about 30 minutes until they are puffy and doubled in size. Leave the oven door ajar.

Step 6

Remove the baking sheets from the oven and preheat to 375°F (190°C). Brush the tops of the dough pieces lightly with milk. Bake one baking sheet after another for about 10-12 minutes until golden brown. Let cool for about 5 minutes then brush the tops lightly with the remaining melted butter and generously dust with powdered sugar. Serve immediately.

Step 7

Note: If you plan to eat them on the next day, you can warm them in the microwave for about 10 seconds if desired. Brush with butter and dust with sugar just before serving.