Prepare the cake batter by combining flour, baking powder, baking soda, and salt in a bowl.

In another bowl, cream together softened butter and granulated sugar until light and fluffy.

Add the egg and vanilla extract to the butter mixture, mixing until well combined.

Gradually stir in the dry ingredients, alternating with the whole milk, until the batter is smooth.

Pour the batter into a greased cake pan and bake in a preheated oven at 350°F (175°C) for 30 minutes or until a toothpick inserted comes out clean.

Let the cake cool completely.

Crumble the cooled cake into a large bowl and mix in icing sugar, softened unsalted butter, additional whole milk, and vanilla extract until the mixture is moist and can hold its shape.

Form the mixture into small balls and insert lollipop sticks into each ball.

Freeze the cake pops for about 30 minutes until firm.

Melt the pure white chocolate and coconut oil together in a microwave or double boiler.

Dip each cake pop into the melted chocolate, ensuring it is fully coated, then garnish with assorted sprinkles.

Allow the coated cake pops to set on a parchment-lined tray.