Preheat the oven to 350F degrees.
Cut the softened butter in 4 pieces and place in a 4 quart food processor.
Pulse the butter, scraping down the sides between pulses.
Add the cheese and pulse until combined, scraping down sides between pulses.
Add the flour and pulse until mixture forms a ball on the side of the bowl.
If you are adding chopped pecans to the dough, add them now, then pulse two or three times just until combined. You can finish mixing them in with a spatula so you don't overwork the dough.
Using a cookie scoop or your fingers, divide dough into 32 (one tablespoon) portions. You can also divide them into 16 (two tablespoon) portions for larger cheese wafers.
Then, roll each portion into balls and place on parchment paper-lined baking sheets. Using your fingertips, gently flatten the cheese wafer balls.
Place a pecan half on top of each one and press down slightly.
Bake for 15 minutes for smaller cheese wafers and 16 minutes for the larger cheese wafers. Remove from oven when the bottoms of the cheese wafers are slightly browned and the tops are firm. The edges will be slightly golden brown.
Let the cheese wafers cool on thebaking sheet 1 minute, then transfer them to a wire rack to cool completely.