Pre heat over to 220C.
Add half the oil to fry pan and lightly toast almond meal on low heat. Remove from pan and put aside.
Heat remaining oil in fry pan and cook garlic, onion and pancetta, stirring, until onion browns lightly. Stir in spinach and remove from heat.
Gently stir in almond meal, nuts and stock (chicken sachet).
Place pork on board, fat side down, slice through thickest part of the pork horizontally, without cutting through the other side. Open out pork to form one large piece; press stuffing mixture against loin along width of pork. Roll pork to enclose the stuffing, securing with kitchen string at 2cm intervals.
Place rolled pork in oven in a large shallow baking dish, roast uncovered about 1 1/4 hours or until cooked.
Remove from oven and cover pork with foil, stand 10 minutes before slicing.