The business of May involved a special project for Mister. His fast-approaching first birthday made me want to give him something unique, something memorable, something that said, “Your Mom’s heart was exploding with love on your first birthday.” No pressure, right? Thankfully, I think I pulled it off!

I’ve talked about how baby boys are often overlooked when it comes to décor and clothes, and I have been determined to find fun options for Mister. His clothes are inspired entirely by Dave—a little preppy, a little casual, a whole lotta cute. When I thought of making Mister a birthday quilt, it was only natural to use his newborn to 12-month baby clothes.


    1. The first step was deciding how large I wanted the finished product to be. I opted for a 50×60 inch blanket. It’s standard throw size and big enough to accommodate Mister’s crib long after it becomes a toddler bed.
    2. The next step was to choose a pattern. Mister’s onesies, sleep sacks and swaddle blankets were the main fabrics, and I knew I wanted to offset each piece with a solid neutral color. After a little sketching and online research, I kept seeing triangles.
    3. I found this handy triangle template online that helped me decide on the cutting size: 5 1/2-inch triangles with 1/4-inch seam allowance.
    4. Next is the math:
      50-inch width/5-inch triangles=10 triangles
      60-inch height/5-inch triangles=23 triangles

How to Make a Onesie


230 triangles is hefty amount and I didn’t have enough onesies and blankets to cover the square footage. I also wanted to emphasize each pattern with a little contrast. I opted to incorporate navy blue linen between each onesie triangle.

I began by gathering a pile of Mister’s clothes and blankets for the quilt.

How to Make a Onesie

I used a seam ripper to create a collection of flat pieces. I winged this step and eyeballed the pieces that could be used for the triangles.

How to Make a Onesie

Cotton fabric is flimsy and easily frayed, which means that it needed to be reinforced before sewing. I used an iron-on interfacing material by Pellon to get the job done. I used the triangle template to eyeball and cut the shapes (there’s no point in being precise just yet). I cut an interfacing strip, placed and pinned a few onesie pieces.

How to Make a Onesie

This was an intimidating step for sure, but there are a few ways to make it move quick and easy:

  • Be sure to place the interfacing fusible (bumpy) side up.
  • The average interfacing tutorial tells you to place damp cloth over the piece before ironing. I skipped that jazz. I kept the iron on medium heat, medium steam and held it on each piece for about 10 seconds.
  • Less is more when it comes to bonding the fabric to the interfacing. Don’t swipe the iron; hold it gently over each piece and allow the steam to work its magic.
  • Turn the strip over once the fabric is bonded and repeat the process.

I cut the fused pieces and set them aside for the final triangle cutting. I repeated the process with the linen fabric by pre-cutting 5 1/2 in strips and laying them on the interfacing directly.

How to Make a Onesie

Once ironed, I cut the strips apart and cut the triangles with a rotary cutter.

How to Make a Onesie

Cutting 5 1/2-wide strips saved time by allowing me to only cut twice for each triangle. This sliced the linen cutting time in half. After a lot of cutting, ironing, and re-cutting, I finally had a big stack of 230 triangles.


I was so excited to lay out the quilt design after 327 years of cutting! I pieced the triangles out on the floor and moved things around to create a balance. The outermost border is dedicated to darker colors, the second border to stripes, the interior to light patterns, etc.

How to Make a Onesie

I condensed and numbered the rows to make sure I didn’t lose the design. Now on to sewing!

How to Make a Onesie


Assembling the rows is next. I lined up the pointy edges with the blunt edges like so.

How to Make a Onesie

I placed the right sides together and pinned the pieces before sewing on the dotted line.

How to Make a Onesie

I repeated the last two steps to continue assembling the row. It helps to have kitten quality control.

How to Make a Onesie

Once the rows were complete, I pressed open the seams with the iron to make all the pieces flat and ready for assembly!


Sewing the rows together was tough, and I’ll be honest, I wouldn’t call it *perfect,* but a little practice had me moving fast by the end.

I laid the quilt pieces out one more time before pinning and sewing the rows together. I opted to sew them in the following order:

  • Rows 1 &2 (A)
  • Rows 3&4 (B)
  • A&B
  • Rows 5&6 (C)
  • A&B&C
  • Rows 7&8 (D)
  • ABCD
  • Rows 9 & 10 (E)

How to Make a Onesie

Hizzah! I definitely danced around at this point. The last step was creating straight edges on each side. I used the rotary cutter and a ruler to slice the edging triangles a few at a time. Now on to sandwich and complete the quilt!


  1. I began the sandwich by choosing a pre-washed (non-shrink) batting and a khaki-colored linen backing. The batting was cut to the size of the quilt front and I cut the backing with a 3-inch border because I was a little afraid of screwing up the binding. We’ll get to that in a minute.
  2. I laid the backing on the floor and taped it down, pulling the fabric as I went to make sure it was as straight and taut as possible.
    How to Make a Onesie
  3. I laid the batting and quilt front in the center of the backing.
  4. The next step is pinning the sandwich together. I used safety pins to secure every triangle on the outside border and every other triangle as I worked. I recommend moving left to right so you can adjust and straighten the pieces if necessary.
    How to Make a Onesie
  5. Now to adjust the backing size. It was a pain, and I wish I had just cut the 1-inch border from the beginning. I went back and, using a ruler, measured one inch from the quilt front, marking on the backing as I went. This allows the binding to appear straight regardless of whether the quilt front is a perfect 90 degrees. I used the ruler to draw a line through each marking before hand-cutting the border with scissors.


I wanted the quilting threads to be hidden so the triangles could shine. Using a quilting foot on my sewing machine, I opted to sew along the seams where the rows were joined (10 rows, 10 quilting lines). It’s impossible to see from the quilt front (hooray!), but the backing has a nice, simple pattern. I removed the safety pins after all the quilting was complete.

How to Make a Onesie


The last and most exciting step was binding. I used the method that involves folding the backing edge in half, pressing the seam with an iron, folding again, this time, over the quilt’s front edge, and pinning. Using the same quilting foot, I sewed as closely to the binding edge as possible. I also used a helpful tutorial on creating mitered corners here.

How to Make a Onesie


This project was so fun and so rewarding. I love having all of Mister’s first-year memories in one snuggable place!

How to Make a Onesie

How to Make a Onesie
How to Make a Onesie
How to Make a Onesie

How to Make a Onesie

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