Melt the butter and set it aside to cool before combining with the remaining ingredients. Line standard muffin cups with paper liners or coat with nonstick cooking spray. Do not preheat the oven yet; it will be preheated later while the batter rests, allowing the gluten-free starches to soften and hydrate in the liquids.

In a large bowl, whisk together the cooled melted butter, granulated sugar, brown sugar, sour cream or yogurt, eggs, vanilla extract, and orange zest.

Stir in the gluten-free flour, baking powder, baking soda, and salt until no dry flour pockets remain; the batter will be thick. Gently fold in the halved cranberries until evenly distributed.

Preheat the oven to 350°F (175°C). While it preheats, use a large trigger scoop to divide the batter among the muffin cups. With slightly wet fingers, pat the tops even. If desired, gently press additional halved cranberries into the tops.

Let the filled muffins rest at room temperature for about 15 minutes while the oven preheats, allowing moisture to saturate the gluten-free starches and build a fluffy structure.

Bake for 20–22 minutes, rotating the pan halfway through, until a toothpick inserted in the center comes out clean. Cool in the pan for 5 minutes, then turn out onto a wire rack to cool while preparing the glaze.

For the glaze, mix the powdered sugar and orange juice in a small bowl until thin enough to drizzle but thick enough to cling to the tops; adjust with more powdered sugar or juice as needed. Place wax paper under the cooling rack to catch drips. Drizzle the glaze over the muffin tops with a small spoon. Let the glaze set before storing.