Measure flour by spooning into the cup and leveling with a knife for accuracy., Do not overmix batter to keep muffins tender and fluffy., Optional to toast poppy seeds in a dry pan to enhance nutty flavor., Buttermilk can be used instead of milk for richer, tangier taste., Almond flour can replace half the all-purpose flour but not all, to maintain fluffiness., Butter can be substituted with equal amounts of vegetable, coconut, or canola oil., Muffins stay fresh up to 3 days at room temperature in an airtight container, up to a week refrigerated, and can be frozen up to 2 months., Batter can be prepared the night before and baked fresh in the morning., Variations include lemon glaze, white chocolate chips, dried cranberries, or switching almond extract to orange extract.