I'd take the shatter and slowly melt it into some heated oil and let it infuse on low heat while you stir well. Then use it as you would oil normally. I havent dont that but I'd think it would work. The shatter is already activated so you don't have to infuse for long. Long enough to get it to dissolve/blend in as best it can.
RE: Cannabis-Infused Chocolate Cake (Cannabis Edible Recipe)