Preheat oven to 350 °F (175 °C). Spray an 8×4 or 9×5‑inch loaf pan with nonstick cooking spray.

In a bowl, whisk together pumpkin puree, ¼ cup of the granulated sugar, vanilla extract, pumpkin pie spice, and egg until smooth. Set aside.

Open the can of biscuits and slice each biscuit horizontally in half. In a separate bowl, stir together remaining ¼ cup granulated sugar and cinnamon. Coat each biscuit half in the cinnamon‑sugar mixture.

Layer in the pan: start with one coated biscuit half, spread a spoonful of pumpkin mixture, then top with another biscuit half. Repeat stacking until all biscuits and pumpkin mixture are used. Arrange stacks upright in the loaf pan.

Bake for 30–40 minutes, until golden on top and cooked through in the center (center may still be moist and gooey). If it browns too quickly, loosely tent with foil and reduce oven temperature to 325 °F.

While the loaf cools slightly, whisk together powdered sugar, cinnamon, and cream or milk until you have a smooth glaze. Drizzle over warm or cooled loaf as desired.

Allow to cool enough to handle, then pull apart to serve. Store loosely covered at room temperature for up to 2 days.