How can I put a widget on top of another widget, with the top left corners aligned?

I have an inventory system where I have borders as slots, then buttons for the actual items in the inventory. I need the button for the item to go over the border for the correct slot, starting at the top left corner. The item button may be larger than the slot border, so I can’t just add the item button as a child.

I already have an equation to make the button the correct size, now I just need a way to position it correctly.

This would even work for me if I could just make the item button a child of the slot, but allow it to extend beyond the edges of the slot, without taking up any room. In fact, this would work even better.

If this is possible let me know.

To do this in UMG, I wrap both elements inside a Border widget and set both their anchors to top left, then use the border widget to determine the position of that top left corner.