Place the tofu planks on one side of a clean kitchen towel and fold the towel over the tofu (or use a double layer of paper towels). Place a large sheet pan or cutting board on top of the towel-covered tofu and weigh it down with something heavy, such as a cast-iron skillet or a large can of tomatoes. Set aside while you prepare the rest of the ingredients.

On a large shallow plate, combine the flour, garlic powder, salt and pepper and use your fingers to mix them together. Thinly slice one of the lemon halves and juice the other half.

In a large, heavy nonstick skillet over medium-high heat, heat the oil until shimmering.

Dredge the tofu planks in the seasoned flour and knock off any excess (discard any leftover flour or save for another use). Working in batches as necessary, carefully place the tofu pieces in the hot oil and sear until golden brown on each side, 2 to 3 minutes per side. Transfer the tofu to a serving platter.

Add the sliced lemon, lemon juice, capers, white wine and broth to the skillet and increase the heat to high. Bring to a boil and cook, scraping the bottom of the skillet with a wooden spoon to loosen any stuck bits, until slightly thickened, about 2 minutes. Reduce the heat to low and add the butter one piece at a time, stirring to melt each addition before adding the next. Pour the sauce over the tofu and serve immediately.