The edges look set and pull slightly away from the pan
The center looks just set, not wet or jiggly
A toothpick inserted in the center comes out with moist crumbs, not raw batter
The top has a shiny, crackled surface
The brownies no longer look glossy or liquid in the middle
The pan may feel slightly firm when gently shaken
An instant-read thermometer in the center reads about 200°F to 205°F
The brownies continue to firm up as they cool