For many who simply had to have the 90th anniversary Stand Mixer introduced by KitchenAid last year, it was the mixer’s shiny, Candy Apple Red finish that sealed the deal. For others, it was the mixer’s clear glass bowl, whether for its vintage good looks or the practicality of its pouring spout and etched measurement markings. This year, in deference to those who already own a mixer, no matter what the color, KitchenAid will offer the glass bowl as a separate purchase, allowing for the same retro look and added convenience at a fraction of the cost of the anniversary model…