Part 1: Making and Kneading the Dough

1. Combine Dry Ingredients: In the bowl of a stand mixer fitted with the dough hook, whisk together the bread flour, sweet rice flour, granulated sugar, salt, and instant yeast.

2. Add Wet Ingredients: In a separate small bowl, whisk together the lukewarm milk and the egg. Pour this wet mixture into the dry ingredients.

3. Mix and Knead: Turn the mixer on low speed and mix until a shaggy dough forms. Add the softened butter, one tablespoon at a time, waiting until each piece is incorporated before adding the next. Once all the butter is added, increase the speed to medium and knead for 8-10 minutes. The dough should become smooth, elastic, and pull away from the sides of the bowl. It will be soft and slightly tacky. (You can also do this by hand on a lightly floured surface; it will take about 15-20 minutes of kneading).

Part 2: The First Proof (The Rise)

1. Form and Rest: Lightly grease a large bowl with oil. Form the dough into a smooth ball and place it in the bowl, turning it once to coat it lightly with oil.

2. Let it Rise: Cover the bowl with plastic wrap or a damp kitchen towel. Place it in a warm, draft-free spot and let it rise for 1 to 1.5 hours, or until it has doubled in size.

Part 3: Shaping the Twists

1. Degas and Divide: Gently punch down the risen dough to release the air. Transfer it to a lightly floured surface and divide it into 12 equal pieces (each should be about 55-60g).

2. Roll into Ropes: Roll each piece of dough into a long rope, about 10-12 inches long. Let the ropes rest for 5 minutes; this allows the gluten to relax, making them easier to twist.

3. Create the Twist: Take one rope of dough. Fold it in half. Hold the looped end with one hand and use your other hand to twist the two strands together a few times. Finally, take the two loose ends and pass them through the loop, gently pinching to seal. Place the shaped donut on a parchment-lined baking sheet. Repeat with the remaining dough, spacing them a few inches apart.

Part 4: The Second Proof and Frying to Perfection

1. The Final Rest: Cover the shaped donuts loosely with plastic wrap and let them rest in a warm place for another 30-45 minutes, or until they look visibly puffy.

2. Heat the Oil: While the donuts are proofing, pour the oil into a large, heavy-bottomed pot or Dutch oven. The oil should be at least 2-3 inches deep. Heat the oil over medium heat to 350°F (175°C). Use a candy or deep-fry thermometer for accuracy.

3. Fry in Batches: Carefully place 2-3 donuts at a time into the hot oil. Do not overcrowd the pot. Fry for 1-2 minutes per side, or until they are a deep golden brown.

4. Drain and Coat: Use a spider strainer or slotted spoon to remove the donuts from the oil and place them on a wire rack to drain for about 30 seconds. While they are still hot, toss them generously in the prepared cinnamon-sugar mixture until fully coated.

5. Serve: These are best enjoyed warm and fresh!