The hot new kitchen gadget for chefs takes its cue from cutting-edge manufacturing. Cooks with an engineering bent can now make elaborate shapes out of food using a three-dimensional printer. The 3-D printers can be filled with chocolate, meringue, avocado, and even meat. The Dutch firm byFlow, for example, recently introduced the Focus, a $4,300 machine sold mainly in Europe. The company is working with Verstegen Spices & Sauces to develop filling cartridges, starting with a paste made of beetroot and cardamom.