• Grease or line a standard 12-cup muffin tin and set it aside. Preheat your oven to 350°F.
• In a large bowl, place the flour, xanthan gum, baking powder, baking soda, salt, 3/4 cup granulated sugar, lemon zest, and poppy seeds, and whisk to combine well.
  2 cups all purpose gluten free flour, 1 teaspoon xanthan gum, 1 teaspoon baking powder, 1/2 teaspoon baking soda, 1/2 teaspoon kosher salt, 3/4 cup granulated sugar, 2 tablespoons poppy seeds, Zest and juice of 1 medium lemon (3 tablespoons juice)
• In a separate, 4 cup measuring cup or bowl, place the butter, sour cream, lemon juice, and eggs, and whisk until very well combined and smooth.
  8 tablespoons unsalted butter, 1 cup sour cream, 3 eggs
• Create a well in the center of the dry ingredients, and pour in the wet ingredients. Mix until just combined.
• Fill the prepared cups of the muffin tin full. Smooth the tops of the batter with wet fingers.
• Sprinkle the tops lightly with more granulated sugar (about 1/8 tesapoon per muffin).
  3/4 cup granulated sugar
• Place the muffin tin in the center of the preheated oven, and bake for about 20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
• Allow the muffins to cool in the muffin tin for about 5 minutes before transferring them to a wire rack to cool before serving.

Storage instructions

• Completely cooled muffins can be sealed tightly, then frozen. Defrost at room temperature or in a microwave oven.