My favorite way is to make 8 at a time.
For 2 1/2 in use two 6 in sqs. draw an x and sew down both sides of lines. Cut in half both ways then on lines. Square up slightly. I like Quilt In A Days triangle sq up ruler as it only requires one cut.
For larger sizes just add 2 in to squares. 8 in for 3 1/2.
And no bias edges.