Generously butter a muffin tin. Preheat the oven to 375℉.
In a large bowl, whisk together the 2 ½ cups gluten free flour , 3 teaspoons baking powder,½ teaspoon fine sea salt, and ½ cup granulated sugar. Lightly whisk the 1 large egg separately, then stir in the beaten egg, 1 cup whole milk, and ¼ cup unsalted butter. Gently fold in the 1 cup raspberries.
Spoon the batter evenly into the muffin tin (fill each cup about two-thirds full). and let the batter rest for up to 20 minutes. Bake the muffins for 15-20 minutes, until a tester comes out clean.
Place the muffin tin on a wire rack to cool for about 10 minutes, then gently turn out the muffins onto the rack to cool completely.
Notes
Rest the batter. Always let gluten-free batter rest before baking - the amount of time it takes to preheat the oven usually is enough - to fully hydrate the flour. You will be able to taste the difference in the final muffin!
Grease the pan well. It's a good idea to generously grease the muffin tin to help the muffins release super easily. Of course, you can always use liners.
Fill the muffin cups about ⅔ full for this recipe. For this recipe, I’ve found that about ⅔ full is the sweet spot so that they rise nicely but don’t overflow the pan.
Make them dairy-free. To make these muffins dairy-free, use melted coconut oil or non-dairy butter and your favorite non-dairy milk.
Refined sugar-free. Add honey to the batter instead of the sugar for a lovely, floral sweetness that's a wonderful complement to the blueberries. Or, try coconut sugar or maple syrup.
Whole grain goodness. You can use whole grain gluten-free oat flour as the only flour in this recipe, or swap 1 cup of oat flour or brown rice flour with the gluten-free flour to add a nice whole grain component.