Make the dough and let it rise.

1. In a measuring cup or medium bowl, add in the lukewarm non-dairy milk, melted vegan butter, and sugar. Mix until dissolved, and then add in the yeast. Set it aside to activate for 8-10 minutes, or until foamy.
2. To a large bowl, add the flour, baking powder, and salt. Mix until uniform. Pour in the activated yeast mixture. Mix together until a smooth dough forms.
3. Transfer the dough to a floured work surface. Knead for 7-10 minutes, or until the dough is smooth and you can stretch a small piece of the dough thin enough for light to pass through without the dough tearing.
4. Place the dough into an oiled bowl and cover with a damp towel or plastic wrap. Set it aside in a warm place to rise until doubled in size, about 60-90 minutes.

Caramelize the onions. 

1. Melt two tablespoons of vegan butter in a saucepan over medium heat.
2. Add the sliced onions, salt, and sugar, and combine.
3. Lower the heat to medium-low and cook, occasionally stirring.
4. After 10 minutes, add the garlic and thyme sprigs and stir.
5. Cook until the onions are deeply caramelized, about 30 minutes. If the onions begin to burn or stick, add a splash of water as necessary. 
6. Remove the thyme sprigs and set the onions aside to cool.

Meanwhile, prepare the filling.

1. Leave the remaining 6 tablespoons of vegan butter out to come to room temperature.
2. Once the butter is softened and the caramelized onions are cooled, add them to a medium bowl along with the vegan mozzarella, vegan parmesan, and black pepper. Mix until well-combined.

Shape the loaf.

1. Once the dough is done rising, roll it out to a 12×16” rectangle. Spread the filling evenly over the dough.
2. Cut the dough into 12 squares, roughly 4×4” each. Fold each square in half, filling side in, and place them into a loaf pan one by one, open side up.
3. Cover and set aside in a warm place to proof for 45 minutes.

Bake and serve.

1. 20 minutes before the loaf is done proofing, preheat the oven to 350˚F. 
2. When the dough is done proofing, place the loaf tin on a small baking tray in case the butter bubbles over. Bake for 40-45 minutes or until the bread is browned on top.
3. Allow the bread to cool for 10 minutes before serving. 
4. Brush with additional melted butter and garnish with chopped chives, and enjoy!