Press the 10 oz block of firm tofu for about 15 minutes to remove excess liquid, using a tofu press or a weight wrapped in paper towels.
Tear the pressed tofu into bite-sized pieces by hand, starting by halving or making larger pieces then pulling into smaller pieces; set aside.
In a mixing bowl combine 4 Tbsp soy sauce (or tamari), 2 Tbsp balsamic vinegar, 1 Tbsp maple syrup, 1/2 tsp dried thyme, 1/4 tsp sweet smoked paprika, and 1 Tbsp molasses (if using); whisk until smooth.
Pour the marinade over the tofu pieces and gently stir to coat without breaking them; let rest for 15 minutes, then reserve the excess marinade.
Add 1 Tbsp cornstarch to the marinated tofu and toss gently to coat evenly, taking care not to break the pieces.
Heat 3 Tbsp of the vegetable oil in a large skillet or cast-iron pan over medium-high heat until shimmering.
Fry the tofu pieces in batches, placing them in the hot oil and cooking 2–3 minutes per side until golden and crisp; transfer to paper towels to drain excess oil.
Mix the reserved marinade with an additional small amount of cornstarch in a small bowl to make a smooth slurry, ensuring there are no lumps.
Pour the marinade into the skillet and bring it to a boil over medium heat, stirring until it thickens slightly into a glaze.
Add the fried tofu to the pan and toss or stir to coat each piece evenly with the sauce; cook 1–2 minutes more, then remove from heat and serve.