1. Preheat your oven to 375 F (190 C). Line a baking sheet with parchment paper or a silicone baking mat.

2. In a large mixing bowl, whisk together the all-purpose flour, 1/2 cup granulated sugar, baking powder, baking soda, 1/4 teaspoon salt, and 1 teaspoon ground cinnamon until well combined. Make sure there are no lumps in the dry mixture.

3. In a separate medium bowl, whisk the egg, milk, 1/4 cup melted butter, and sourdough discard until smooth. The discard should be fully incorporated into the liquid mixture.

4. Pour the wet ingredient mixture into the dry ingredient mixture. Stir gently with a spatula or wooden spoon until just combined. Be careful not to overmix; a few lumps are perfectly fine and will lead to a tender muffin top. Overmixing can result in tough baked goods.

5. Drop spoonfuls of the batter onto the prepared baking sheet, leaving about 2 inches between each mound. Aim for about 1/4 cup of batter per muffin top, shaping them into flat, round discs. Bake for 12-15 minutes, or until the edges are lightly golden brown and a toothpick inserted into the center comes out clean.

6. While the muffin tops are baking, in a small shallow bowl, combine the remaining 1/4 cup granulated sugar and 1/2 teaspoon ground cinnamon. Melt the remaining 2 tablespoons of butter in a separate small bowl.

7. Once baked, immediately remove the muffin tops from the oven. While still warm, brush the tops with the melted butter, then dip them generously into the cinnamon sugar mixture, ensuring they are fully coated. Serve warm and enjoy!