NOTE: This tutorial assumes you have some experience with cookie decorating. For the basics I recommend visiting The Sweet Adventures of Sugarbelle, Sweetopia, and the Decorated Cookie or check out these booklets that they helped me put together for National Sugar Cookie Day.
STEP1. PLAN! You can't just dive into this project without thinking it through (which is what I usually do). First - decide on the quilt pattern you're going to make and how large you want your finished cookie quilt to be. That will determine how many cookies you'll need to bake and how big they should be. In this case I needed to make 5 dozen cookies so to make the math work out correctly, I chose this pinwheel pattern consisting of 4 squares per block with a total of 15 blocks. My cookies are 3 1/2" square.
STEP 2. Mix up some sugar cookie dough, roll and cut. Choose a recipe that maintains its shape/doesn't spread too much when baked. Try to roll the dough to a consistent thickness so your cookies end up being the same size after they're baked. Then - wash your quilting ruler with warm soapy water and get out your pizza cutter (or use any straight edge and a sharp knife). Cut the dough into squares (whatever size you've decided) and bake.
STEP 3. Prepare Royal Icing. Tint the icing to all of the colors that you will be using and thin the icing using the 10 second rule. If you're making the pinwheel pattern - outline then flood 1/2 of each cookie with white icing.
STEP 4. Now - You'll make the patterned "fabric". The pattern/design is made by flooding the cookie with thinned icing and then piping the design with thinned icing (in a different color) while the flooded icing is still wet. (Does that make sense?) Outline then flood the other half of each cookie with colored icing according to your pattern but only flood 2 or 3 cookies at a time. Then pipe your design (with thinned icing) on top.
TO MAKE POLKA DOTS: Using a #2 tip - Hold your pastry bag so that the tip is straight up and down and carefully dot the flooded icing (with thinned icing) lifting straight back up.TO MAKE SMALL FLOWERS - Using a #1 tip - Just pipe a starburst/asterisk with thinned icing (make an "x" then cross through the center horizontally and vertically) then dot the center with thinned icing in another color. The icing will spread a little so that it looks like a flower.
Using the technique of piping thinned icing on still wet flooded icing, you can create simple stripes or big "scribbley" flowers or whatever you want. The piped designs will "sink" into the flooded icing and the result will be a smooth cookie that looks like fabric. (Just try to make sure you're thinning you're icing to approximately the same consistency).
Once all of your cookies are decorated - it's just a matter of laying them out side by side according to your pattern to form your quilt.
Happy quilt baking!
Please let me know if you have any questions or if I can clarify anything! I usually end up writing tutorials like this early in the morning or right before bed so I don't know how much sense they make!