Heat oven to 425 degrees. Heat cast iron pan for 5 minutes, adding butter to pan just prior to pouring in the egg mixture.Butter needs to be melted and hot!While oven is heating mix eggs on high for about 1-2 minutes until pale and foamy. Add vanilla or almond extract, and salt. Blend for 20 seconds.Turn mixer on to fold or low, gradually adding flour, then pour 1/3 c. milk in all at once mix on low for 20 seconds max. Pour immediately into HOT PREHEATED cast iron pan, bake for 5-7 minutes or until giant and fluffy, and golden brown. Dust with powdered sugar, add fresh berries or maple syrup.