Heat the oven to 190C/fan 170C/gas 5. Butter 6 holes of a large muffin tin. Unroll the dough and pull apart the sections. Cut the long end off each triangle, then use each section of dough to line a hole. Spread the ham slices with the jam then tuck a slice inside each croissant cup.
Crack the eggs into a glass first then tip them into each croissant. Season and bake for 15 minutes until the croissant is puffed and golden, and the egg is cooked.