Preheat the oven to 500°F (260°C) and pop a pizza stone (or a heavy-duty baking sheet) on the bottom rack of the oven.
Heat the olive oil over medium heat in a heavy-bottomed skillet. Add the onion and season with salt. Cook until caramelised, stirring occasionally.
Divide the pizza dough into 4 equal portions. On a lightly floured surface, roll each out to a ~5-inch circle.
Spread ¼ of the Birria stew (just the broth) over each pizza, leaving ~½ inch boarder. Evenly distribute (in order) the following ingredients between the 4 pizzas: vegan mozzarella cheese, Birria meat, caramelized onion, pickled jalapenos, and vegan Mexican blend cheese.
Pull the pizza stone (or baking sheet) out of the oven and scatter a couple of tablespoons of cornmeal over the top. Transfer 2 of the pizzas to the pizza stone (or baking sheet) and bake for 10-15 minutes or until the crust is puffy and blistered and the vegan cheese is melted and bubbly. Repeat with the remaining cornmeal and remaining pizzas.
Serve warm, garnished with chopped fresh cilantro, and drizzled with extra Birria stew (just the broth).
Notes
To store: Wrap individual slices of this birria pizza in foil or place the slices in an airtight container. Store leftover pizza in the refrigerator for up to 3 days. When you're ready to enjoy your leftovers, simply reheat in the oven at 450°F until warmed through, use the microwave, or eat it cold.To freeze: I like to wrap each slice in plastic, then place them in an airtight container or freezer bag. Freeze for up to 2 months. I recommend thawing the pizza in the refrigerator before reheating, which helps the reheating be more even.