Hot vs Cold Chinese culinary standards
I would go with 'yang' for seared lamb.

I come from a Chinese family that owned a restaurant for some time. Yin has always been characterized as gentle or moist cooking techniques such as steaming, braising or simmering (gau yuk aka kau yuk). Yang has always been characterized as abrupt or dry cooking techniques such as searing, frying or roasting (stir fry, crispy duck). Crispy duck is actually a combination of yin and yang, as it is first braised then seared. Don't listen to me, I've been brain washed.

Edit: In cooking I would consider 'yang' as intense or harsh and 'yin' as gentle, rather than hot and cold.