Preheat the waffle maker - Preheat the waffle maker according to the manufacturer's instructions, and preheat the oven to 200°F (93°C) to keep the already cooked waffles warm. The waffle maker may take a few minutes to heat up, so you can use this time to prepare the waffle batter. - Make sure your waffle maker is clean and prepared with cooking spray before preheating it. You can also use non-stick cooking spray with flour for extra non-stickiness to give your waffles a perfect golden brown color.

Combine the dry ingredients - In a large mixing bowl, whisk together the flour, baking powder, salt, and sugar until blended. - Sift the dry ingredients through a fine-mesh strainer for an even smoother batter without any lumps.

Combine the wet ingredients - In a separate bowl, whisk together the milk, vegetable oil, and vanilla extract until smooth and well-combined. - Make sure your wet ingredients are at room temperature to avoid clumps and to help the ingredients to blend together more easily.

Add the wet ingredients to the dry ingredients - Pour the wet ingredients into the dry ingredients, and stir gently with a rubber spatula until just combined. Do not overmix the batter to keep the waffles fluffy and light. A few small lumps may remain, but that's okay. Fold in the rainbow sprinkles until evenly distributed. - Do not use an electric mixer or overmix the batter, as this will activate the gluten in the flour and make the waffles tough and chewy. If the batter is too thick, add a splash of milk and stir gently.

Cook the waffles - Ladle the batter onto the center of the hot waffle maker, and cook according to the manufacturer's instructions until the waffles are golden brown and crisp. Transfer the cooked waffles to a baking sheet and keep them warm in the oven while cooking the remaining batches. - Avoid opening the waffle maker prematurely, which can cause the waffles to stick and become misshapen. Keep an eye on the waffles, and remove them from the waffle maker promptly when they are cooked.

Serve and enjoy - Serve the waffles warm with your favorite toppings, such as whipped cream, syrup, or fresh fruit. Enjoy your colorful and festive waffle delights! - Try serving the waffles with different toppings, such as Nutella, peanut butter, or ice cream, or experiment with different flavors of extracts and sprinkles to customize your waffles according to your taste.