Measure and cut the mat to fit in the frame on the cardboard. I cut it a little bit bigger so that I could easily trim it to fit the frame.
Find the center of your mat by turning the mat over and drawing two diagonal lines to over cross each other with your metal ruler. Place your 3x5 card in the center of the diagonal lines and trace around the edges. Using your utility knife and metal ruler cut out the rectangle.
Tape the back of index card. To do this, lay the front of the 3x5 card face down and put a piece of tape over the top. You don't want a lot of tape hanging off the edge.
To attach the 3x5 card lay the mat face down. Turn the 3x5 recipe card over, and place it within the 3x5 opening on the mat. Once you have desired placement, press the card down with the tape to have it stick to the mat.
Place the mat with the attached recipe card in the frame.
Voila! You have a lovely framed recipe ready to be hung.
To make the recipe stand out you can also use thick mounting tape