It may seem like a fussy step to let both the batter and the streusel rest at room temperature, but it is important. The starches in gluten-free flour—usually potato starch or cornstarch—need time to absorb enough liquid to lose their chalky mouth-feel. The payoff for your patience? Moist, tender muffins with a delicate crumb. Slideshow: More Gluten-Free Desserts
How to Make It
Line a 12-cup muffin pan with paper or foil liners. In a medium bowl, whisk the flour with the cinnamon, baking soda, pumpkin pie spice and salt. In another medium bowl, whisk the pumpkin puree with the brown sugar, butter, eggs, milk and orange zest until smooth. Add the dry ingredients and whisk until the batter is evenly moistened. Fold in the golden raisins, if using. Let the batter stand at room temperature for 1 hour.
In a small bowl, whisk the brown sugar with the flour, oats, pumpkin seeds, salt, cinnamon and pumpkin pie spice. Drizzle in the melted butter and stir until clumps form. Let the streusel stand at room temperature for 30 minutes.
Preheat the oven to 350°. Scoop the batter into the lined muffin cups and sprinkle the streusel on top. Bake for 30 to 35 minutes, until a toothpick inserted in the center of a muffin comes out clean. Transfer the muffins to a rack to cool completely before serving.