Heat a tablespoon of the oil over a medium-high heat, then add the tofu. Fry, stirring occasionally, for 10 minutes, until the tofu is browned on all sides. Remove it from the pan and place to one side.
In the same pan, heat the remaining oil. Reduce the heat to medium, then add the onion. Fry it for 3 minutes until it begins to soften, then add the minced garlic cloves. Fry for 2 minutes more until it’s aromatic.
Grind you peppercorns using a pestle and mortar until they are very coarsely ground. Alternatively, pulse them in a spice grinder.
Add the soy sauce, vinegar, water, ground peppercorns, bay leaves and sugar to the pan. Stir to combine, then bring the sauce to a simmer. Simmer for 10 minutes.
To thicken the tofu adobo sauce, add the cornstarch slurry then stir to mix. Continue to simmer and the sauce will thicken within a couple of minutes.
Remove the bay leaves, then add the crispy tofu and stir until it’s covered in sauce.