The front cover of today’s Globe food section carries a picture of a young man munching on a delicious-looking chocolate frosted doughnut that made me want to run out and buy a half-dozen. The accompanying story discusses the “best” independent doughnut shops in Greater Boston which got me wondering which place has the best doughnuts in Greater Lowell. When I was younger, my two favorites were Mary Lou’s on Chelmsford Street and Eat-a-Donut at Liberty and School. They’re both gone now and I’m more likely to grab a muffin with a coffee than a doughnut. Still, every once in a while, a freshly cooked, sugary and sticky doughnut would be nice. Any suggestions?