Preheat the oven to 350 degrees F.
Place the muffin liner in a muffin a cupcake pan. Set aside.
In a mixing bowl, add the oatmeal and ½ cup of milk. Set aside.
In a separate bowl, mix the flour, baking soda, ground cinnamon, salt, and raisins. Mix until the raisins are coated with the flour mixture. Set aside.
In a large mixing bowl, mix the egg, light brown sugar, maple syrup, melted butter, and vanilla paste. Mix until all ingredients are combined.
Add the oatmeal mixture and remaining milk and mix well.
Add the flour mixture, in 2 or 3 increments, alternating with the rest of the milk, until there's no more dry flour. Don’t over-mix. I used a Danish dough whisk. You can also use a hand mixer, just add the flour in small increments.
Use a large cookie scoop, 3 tablespoons, and scoop the batter into the prepared muffin pan.
Bake in the preheated oven for 16 to 18 minutes.
Cool for a few minutes in the muffin pan and transfer to a cooling rack to cool completely.