Preheat oven to 400 degrees
Heat oil in your dutch oven and throw in your chicken breast and let cook for 2-3 minutes per side and remove
Throw in 4 tbsp of butter and your diced onion and let soften before throwing in your minced garlic (low-med heat) you don't want garlic to burn
Add in your flour and allow it to fully cook out (about 2-3 minutes)
Pour in your chicken broth, seasonings, and heavy cream and allow to come up to a simmer
Throw in your potatoes (halved) and let simmer for 4-5 minutes before throwing in broccoli and chicken
Pop in the oven for 15-18 minutes until potatoes are fork tender and chicken is cooked through