Before anything, prep the broccoli. Thaw in a covered, microwave-safe bowl with 2 tablespoons of water in the bottom. Cook broccoli for 3-4 minutes, long enough to defrost it, but not cook it completely. If using fresh broccoli, skip this step.
Melt the butter in a pot or dutch oven.
Add onion and cook until translucent.
Add flour to the onion and butter in the pan and stir until combined.
Cook flour mixture for about a minute.
Stirring constantly, heat until mixture comes to a boil and thickens.
Add the rest of the ingredients.
Once the fricasse reaches a simmer turn the heat down to medium, cover and cook for ~30 minutes, stirring occasionally. It's done when the vegetables are tender.