To put more space/distant in between

In the context of the sentence, "space out" means to increase the gap or distance between the triangular chunks of Toblerone chocolate in the bar. This was done by widening the spaces between the individual triangles in the bar, reducing the amount of chocolate used in the product and ultimately keeping production costs down. The change in design was met with criticism from some consumers who were disappointed with the alteration to the traditional shape of the Toblerone bar.