Some tips from Mark Sisson on keeping kosher. He is the author of the primal blueprint so I will reference his work a lot. However the primal/paleo lifestyle is quite extensive book and research wise so I will reference other people as well. I use Spectrum Vegetable shortening (palm oil) and Spectrum Unrefined/refined(better for high heats) Coconut oil for a lot of cooking. I also use shmaltz (chicken fat, or the goose fat) occasionally, but it is high omega 6 and it tends to make me sleepy. So for big dinners shmaltz will bring back that flavor you missed when you were a kid. Since my website is basically about applying this to daily life, this will be covered in much more depth than presented here.
You’re in luck. The only tenets that would impact the Primal nutritional “targets” might be the shellfish restriction and the no-meat-with-dairy law. As I mentioned in the post on shellfish, oysters are the richest sources of dietary zinc, an important mineral lacking in many modern diets. Getting zinc elsewhere is easily accomplished – just eat lean beef shoulder (100 grams gets you 10 mg), lamb, or bison. And since dairy technically resides in a Primal gray area (despite the community’s general acceptance and adulation of grass-fed butter), you’re not missing much. Olive oil, coconut oil, beef tallow (as long as you avoid tallow rendered from the fat that lines the cow’s organs; that’s called chelev and it’s definitely not kosher), and palm oil are all fine cooking fats that don’t upset the kosher dietary laws.