There’s something to be said for doing just one thing really, really well. And Hastings resident Sarah Simon’s addictive cookie bars, Sarah’s Caramellas (gift box of 4 for $10 at sarahscaramellas.com), fall into the Do One Thing Well category. Sugary without being cloying, these bars are three layers-thick: an oat-and-brown-sugar base, topped by walnuts and caramel, and finished with a semi-sweet/regular milk chocolate combo topping. Find ‘em at the following markets: Black Cat Café in Irvington, Coffee Labs Roasters in Tarrytown, Dragonfly Caffe in Pleasantville, Julie Bean Espresso, Mobile Cafe (juliebeanespresso.com), and Manor Market in Hastings.