4 fat quarters
Step 1: Take the two pieces you want for the main apron piece and square them up so they're exactly the same size. Then fold them each in half hamburger style and stack them one on top of the other. Use something circular like a plate to round one of the loose corners. Set them aside.
Sew the three pieces together end to end so you have one long strip. Iron open the seams.
Iron the strip in half, right sides facing out.
Then open the strip up again and iron the two ends up toward the center. If you want your bias tape to be awesome, iron one side all the way up into the crease and the other side about 1/8" away from the crease.
Fold the strip back on that original center fold and iron again. If you did the fancy step you should have one side that is just a smidgen bigger than the other.
With the wrong side facing up, iron in the edges with a 1/4" seam all the way around both pieces.
Fold each in half and iron in place.
Then stitch around each with a 1/8" seam to secure the edge.
Sew two of the pieces together at the ends so you have two long strips. Iron your seams open.
Fold the strips in half lengthwise with wrong sides together. Pin.
At one end of each strip mark a 45 degree angle down to the corner. Sew each strip leaving the non angled end open.
Turn the strips right side out. Use a turning tool to poke out the points and iron. Top stitch around each tie.
Step 8: Take your 7" piece from before and with it wrong side up, iron in 1/4" seams along all four edges. To make things easier on yourself later, go ahead and stitch the ironed edges in place. I stitched about 1/8" away from the edge. This will keep your seam neat, and also act as a stitch guide for you later on.
Fold in half lengthwise.
Now we're going to test for fit. Place your strips inside the folded piece until the straps hanging beyond the edge are the length you think you want them. pin in place and test fit by tying around your waist. Adjust the straps to the length you want.
When the straps are just the right length, trim off the excess, but so that about 1/2" hangs inside the flap and pin in place.
Take your apron piece and sew a gathering stitch (stitch length of 5) 1/4" from the top. Tie the strings on one end together. Pull on the bobbin thread on the other side and gather the fabric until it is about 1/2" shorter than the wide part of the tie.
Lift the flap and place the main piece inside about 1/2", put the flap back down and pin in place. You're now going to sew around the three sides of the wider part of the tie, the two sides and the bottom.
You're all done. Try it on.
Yes, try it on both ways. Now go make me a sandwich, woman! (Just kidding, I'd rather have some baked goods.)