Defrost the puff pastry, preferably overnight in the refrigerator. (You can defrost on the countertop, according to the manufacturer's directions, but be careful not to let it get to room temperature.) It should be chilled but not so cold that it is still stiff when you unroll it. 

On a silicone mat or piece of parchment, roll out the sheet of puff pastry to a rectangle between 9 x 15-inches and 10 x 16-inches. 

Mix the taco seasoning and 2 - 2 & 1/2 tablespoons of the olive oil. Evenly brush the mixture onto the puff pastry. 

Spread the shredded or grated cheese evenly on top of the seasoning/oil-topped puff pastry. 

Make a line down the middle of the long side of the rectangle (gently with a butter knife or similar, so as not to cut through the dough.) Fold or roll the two long sides of rectangle toward the middle, so you have a single, long log. Gently lift the log onto a cookie sheet and freeze for 20 minutes or refrigerate for 1-2 hours. While it is cooling, pre-heat the oven to 400 degrees F. 

Once the log is well-chilled, remove it from the freezer or refrigerator and cut it into 1/4-inch slices. Place the slices on silicone or parchment-lined cookie sheets and bake for 15-20 minutes. 

After removing the palmiers from the oven, let them cool down on the cookie sheets. Store them in a tightly closed container.