Heat oven to 350°. Butter an 8×8 baking pan (metal preferred), and line with parchment paper. Spread a little extra butter over the parchment and in any exposed corners as well – you’ll be glad you did when it comes time to get them out of the pan.

In medium saucepan, bring an inch or two of water to a simmer and place a heat-safe bowl on top. Add butter pieces to bowl, then sprinkle chocolate chips over top. Heat over simmering water, undisturbed, until butter is fully melted and chocolate is beginning to melt. Remove bowl from heat and mix with a rubber spatula until chocolate is fully melted and the mixture is thick and glossy. Add sugar and mix until combined.

Add eggs one at a time, incorporating with a hand-held mixer or whisk after each one. Stir in vanilla and salt. Dump in flour and gently fold into batter with a rubber spatula until just combined.

Scrape batter into prepared pan and bake at 350° for 25 minutes, or until cake tester or toothpick comes out clean. Don’t overbake or you’ll end up with dry brownies.

Cool brownies in the pan on a rack, then invert onto a clean plate or cutting board and cut into 16 squares.