1. Prepare the pineapple salsa: Dice tomatoes, red onion, jalapeno, and pineapple into small pieces. Combine in a bowl, squeeze in the juice of one lime, and add chopped cilantro. Mix well and set aside.
2. Prepare the tortillas: In a bowl, mix masa harina with warm water until a dough forms. Knead for a few minutes, then divide into small balls. Using a tortilla press or rolling pin, flatten each ball into a thin circle.
3. Cook the tortillas: Heat a cast iron skillet or griddle over medium heat. Cook each tortilla for 1-2 minutes per side, or until lightly browned and puffed.
4. Prepare the Impossible steak bites: Heat olive oil in the same skillet. Add the Impossible steak bites and cook until browned. Add butter, minced garlic, and a sprig of rosemary. Cook for another minute.
5. Prepare the guacamole: Mash avocados in a bowl, squeeze in the juice of half a lime, and season with salt. Mix well.
6. Assemble the tacos: Spread guacamole on each tortilla. Top with the cooked Impossible steak bites and pineapple salsa. Serve immediately.
