Use a tofu press to remove the excess water from the block of extra firm tofu. If you don't have a press, wrap the tofu in a clean kitchen towel or a few paper towels. Place a flat plate (or chopping board) on top of the wrapped tofu, then set a slightly heavy object on the plate. Make sure not to crush the tofu. Press for 5-10 minutes.
Prep The Marinade
While the tofu is being pressed, add the marinade ingredients to a gallon ziplock bag or a 9x13-inch glass dish and mix.
Now slice the tofu into filets. You can cut it into rectangles, triangles, or 1-inch cubes for kababs. Tip: To cut triangles, diagonally cut the tofu in half. Now, stand up the triangles and slice 3 even filets from each half.
Position the tofu slices in the marinade in a single layer. If you're using a baking dish, spoon the marinade over the top of each slice. Marinate for at least 30 minutes to 1 hour, but overnight in the refrigerator will yield the best flavor.
Grill The Tofu
Heat your grill to medium-high heat. When the grill is hot, carefully season it with cooking oil. Allow the oil to cook into the grill for about 30 seconds. Repeat this step.
Now, carefully lay each piece of tofu down. Grill the tofu for 5-8 minutes on the first side. Then flip and cook for another 3-5 min on the other side. Grilling the tofu longer on the first side will allow it to dry out making it easier to flip. If you notice the tofu is sticking to the grill allow it to cook a bit longer. The tofu will pop free from the grill when it is ready to be flipped. (see note)
Serve immediately or keep it warm on the top rack of your grill and brush with marinade to keep it from drying out. You can also remove the tofu filets from the grill and place them back in the remaining marinade. This will bring back any flavors lost during cooking.
To Grill Pineapple Rings
If your grill is large enough, carefully place the pineapple rings down along with the tofu. Grill for 5-10 min, or until the pineapple rings have nice grill marks. For smaller grills, place the pineapple down as you remove the tofu.
Store any extra tofu in an airtight container with the remaining marinade. Keeps in the fridge for 5-7 days.
Notes
To bake the tofu: Bake at 375°F for 15-20 minutes, then flip and bake for an additional 10 minutes or until the tofu is no longer wet.
To precook the tofu: You can use the baking instructions above to prepare the tofu ahead of time, then simply reheat it on the grill. Store the cooked tofu in the remaining marinade until you're ready to grill.
Pineapple Juice: If you're using canned pineapple, use the juice from the can.
Fresh pineapple rings: A normal-sized, whole pineapple can yield about 8-10 slices. You can use 2-3 slices to juice for the marinade, or use apple juice.
Sweetener: I use agave nectar or maple syrup because it easily mixes with the marinade ingredients. I have also tried it with coconut sugar and cane sugar, and they are fine options, but you may find a few sugar granules in the marinade.
If your lemons are very tart, taste the marinade after mixing. It should have a balanced blend of sweet, salty, and tangy flavors. If the lemon is overpowering, add sweetener one teaspoon at a time until the flavors even out.
*For more helpful tips, check out the "Grilling Tips" section in the above post.