[...] when I substituted almond milk, soy milk and lactose-free milk, the popovers came out like hockey pucks. [...] Ralph Burgin, general manager and partner at the Cliff House Restaurant, adds a little high-protein flour to his batter for a crisper crust, and sells a popover mix that contains pastry flour and high-gluten OO flour. -- Mix the batter in a blender, food processor, with an electric mixer or whisk by hand. Remove them to a baking sheet and leave uncovered at room temperature ...