Preheat the oven to 180c fan/200c/395f. Use oil to grease 12 holes of a muffin tin.
In a large bowl, or the bowl of a stand mixer, combine the butter, brown sugar and granulated sugar (medium speed) for about 3-5 minutes until fully combined.
Add the egg and vanilla and mix again.
Fold in the flour, baking soda and white chocolate chips and fold together. Use an ice cream scoop or your hands to form 12 balls of dough, placing each ball into a hole in the muffin tin.
Bake for 15-18 minutes, until golden on top.
Remove from oven, and use a small jar or similar (I use an egg cup/1/4 cup) to create indentations in the middle of each cookie cup. Let cool.
Once cool, add 1 tsp jam into each of the little wells in each cookie cup. Make the glaze by combining the powdered sugar and milk. It should be pourable but thick. Once at this stage, pour a little onto each cookie cup. Enough to cover the jam.
Top with sprinkles and let set for an hour or so before serving.