Prepare the dough: (sub out the avocado oil with basil pesto).

Make the tangzhong:

• In a small saucepan over medium heat, combine together the milk and flour.
• Whisk until the mixture thickens, about 3-4 minutes. The paste will appear quite thick and gluey.
• Remove from heat. Let cool slightly.

Make the dough:

• Combine the yeast, sugar and warm milk in a bowl. Give it a stir and leave for a few minutes until the yeast becomes bubbly.
• Add the flour, salt, egg and oil into a stand mixer bowl fitted with a dough hook attachment.
• Pour in the activated yeast mixture, lightly cooled tangzhong mixture, and knead until the dough becomes smooth, shiny and elastic.
• The dough will be slightly tacky and you may want to finish kneading the dough with your hands.
• Transfer the dough to a lightly greased bowl and cover with a cloth or plastic wrap.
• Let the dough rise in a warm location, anywhere from 1-1.5 hours, or until doubled in size, depending on how warm your kitchen is.

Prepare the meatballs:

• If using homemade meatballs, make sure they’re fully cooked and cooled.
• If using frozen meatballs, thaw at room temperature, or microwave until completely defrosted.
• Small or golf ball-sized work best. Set aside.

Assemble:

• Preheat oven to 375°F/191°C.
• Line a baking sheet with parchment paper.
• Punch down the dough and divide into 12 equal pieces, about 46g each.
• Roll each piece into a long rope, about 8" long.
• Make a knot and tuck the tail ends (in the middle).
• Press a meatball firmly in the center.
• Repeat with the remainder.
• Loosely cover and leave to rest in a warm location until slightly puffy.
• Brush pesto onto the tops of the dough.
• Sprinkle with cheese, if desired.
• Bake for 18-20 minutes at 375°F/191°C, or until lightly golden in color.
• Brush with more pesto while warm, if desired.
• Serve warm with marinara sauce, or extra pesto.