Preheat the oven to 400°F. Line a baking sheet with parchment paper. Set aside.

In a medium bowl, whisk together the sugar, flour, baking powder, baking soda, and salt until well combined.

In a small bowl or measuring cup, whisk together the sour cream or yogurt, egg, milk, and vanilla until smooth.

Using a fork, stir the wet ingredients into the flour mixture until dough clumps start to form. Add in the cinnamon chips and continue to mix until large dough clumps form. Use your hands to press the dough against the sides of the bowl to form a ball. The dough will be sticky at first, but will come together as you press.

Place dough onto a lightly floured surface and use a rolling pin to roll it into a rectangle about 7x14 inches.

In a small bowl, stir together the filling ingredients until well combined.

Brush the reserved melted butter over the top of the dough, then sprinkle the cinnamon-sugar mixture evenly on top, pressing it down gently with your hands to help it stick.

Starting from one of the short sides, fold one short side of the dough over to meet in the middle of the rectangle. Use a dough blade to help with this. Repeat this fold on the other side, with the two ends meeting in the middle.

Use your hands to gently shape the edges of the dough into a circle (it’s ok if it is more of a rounded square!). Using a sharp knife or dough blade, cut the circle into 8 triangles. Place them 1-inch apart on the prepared baking sheet. Bake until golden, about 15-17 minutes. Cool for 10 minutes while you prepare the glaze.

Make the glaze by whisking the glaze ingredients together in a small bowl until smooth. If needed, add a bit more milk, 1 teaspoon at a time, to reach your desired consistency. Spoon or drizzle the glaze over the scones; allow the glaze to set before serving.