Separate eggs. You'll only use egg whites. Save and refrigerate your yolks for custards, ice cream, or omelets.
Heat egg whites, sugar, butter, and flour until flour is fully dissolved. Stir constantly with a whisk. This will be a very liquidy batter. Then pour into circles on a Silpat pan.
Bake on 250°F/130°C for 30 minutes total. You can do this quicker in high heat oven, but if it's hot outside, try low and slow. About 10 minutes in or when the shells are solid, pull out of the oven and gently and slowly lift them up off the Silpat with a spatula. Roll into cannoli tube shape while oven warm, and then set tubes back in the oven for a remainder 20 minutes of baking.
