Introducing Allergens?

Keisha • Me and Hubby are diagnosed infertile... We`ve been TTC for 15 years now. Finally expecting our first baby February 2022

How are you introducing Allergens to your baby? Using the mix-in powders or giving small samples of real food (and how?). I’m feeding purées but not sure what’s best for introducing allergens. The powders and puffs seem like a long and expensive road… what are your thoughts?