The new “spreadable” butters contain butter and canola oil, and promise “Soft Even When Cold!” “Low in saturated fats and cholesterol!” and “No transfatty acids!” At my local grocery store, an 8-ounce plastic tub of Challenge Spreadable Butter sells for $2.49. We make our own instead, for about 80 cents. Simply whisk together one softened 4-ounce stick of butter (I buy it on sale and freeze it, when it’s $2.50 a pound, or 63 cents a stick) and ½ cup of canola oil (about 17 cents) and add a little sea salt if you like. Spoon it into a container, cover and chill in the refrigerator. Makes 1 cup.