Grease a standard 8x4-inch loaf pan with non-stick cooking spray and line the bottom with a strip of parchment paper for easy removal. Place a metal wire baking rack inside the bottom of your Crock-Pot or slow cooker to elevate the pan.
In a large mixing bowl, whisk together the all-purpose flour, baking soda, baking powder, ground cinnamon, ground nutmeg, ground cloves, and salt until well combined.
In a separate medium bowl, whisk together the pumpkin puree, melted butter, granulated sugar, brown sugar, eggs, vanilla extract, and milk until smooth and uniform.
Pour the wet pumpkin mixture into the dry flour mixture. Gently fold the ingredients together using a spatula until just combined and no streaks of dry flour remain, taking care not to overmix the batter.
Transfer the pumpkin bread batter into your prepared loaf pan, smoothing out the top evenly.
Carefully lower the filled loaf pan onto the wire rack inside the slow cooker.
Cover the slow cooker with its lid. If your lid tends to trap a lot of moisture, place a clean kitchen towel or double layer of paper towels securely across the top of the slow cooker before putting the lid on to catch any dripping condensation. Cook on HIGH for 2 to 2.5 hours, or until a toothpick inserted into the center of the loaf comes out clean.
Carefully remove the loaf pan from the slow cooker using oven mitts. Let the pumpkin bread cool in the pan for 15 minutes, then run a knife around the edges and invert it onto a wire cooling rack. Slice and serve warm for breakfast, as an afternoon snack, or with a sweet glaze for dessert!
Notes
Optional Add-Ins: While this classic base recipe is delicious on its own, you can easily fold in up to $1/2$ cup of optional mix-ins just before transferring the batter to the loaf pan. Popular choices include semi-sweet chocolate chips, mini chocolate chips, or chopped nuts like pecans or walnuts.
Flavor Boosters: Feel free to mix in a handful of dried cranberries, raisins, or a pinch of extra pumpkin pie spice if you want an extra burst of autumn warmth.
Glaze Topping: Once the bread has cooled completely, you can elevate it from a simple snack to a decadent dessert by drizzling it with a homemade cream cheese glaze or a simple powdered sugar and maple syrup glaze.