Preheat the oven to 350ºf and generously spray your mini-muffin pan.
In a mixing bowl, combine the oil, eggs, milk, and vanilla, making sure the eggs are fully incorporated.
In another separate bowl, whisk together the dry ingredients (flour, baking powder, baking soda, salt, sugar) thoroughly.
Gradually pour the dry ingredients into the wet mixture, stirring until just combined. Be careful not to overmix—this will lead to dense muffins that don't rise properly. The mixture should be fluffy and moist.
Stop mixing once the dry ingredients have dissolved into the wet ingredients.
Gently fold in the sprinkles until evenly distributed throughout the batter.
Drop ½ to 1 tablespoon of batter into each spot on a mini-muffin pan.
Bake in the oven for 7 minutes at 350°F (on the middle rack), or until the muffins are fully cooked. You can confirm the cook by the toothpick method.
Allow the muffins to cool in the pan for 5-10 minutes before transferring them to a cooling rack.