Fudgy and Chewy Brownies

I got this recipe online, My Baking Addiction.  According to the site, this is "Fudgy, Chewy, Cakey Brownies from “The Perfect Recipe” by Pamela Anderson".

Ingredients

• 2/3 cup all-purpose flour
• 1/2 tsp baking powder
• 2 oz unsweetened chocolate
• 4 oz bittersweet or semisweet chocolate
• 10 tbsp (1 stick plus 2 tbsp) butter
• 1 cup brown sugar
• 2 tsp vanilla extract
• 3 eggs
• optional: 3/4 cup toasted walnuts, pecans, macadamia nuts, peanuts

Directions:

1. Preheat oven to 160 degrees Celsius. Grease a 8"x8" baking pan and set aside. You can opt to place foil or parchment paper to line the pan. Make sure to grease the insides as well.
2. Combine flour, salt and baking powder in a small bowl and set aside. 
3. In a shallow mixing bowl, melt chocolates and butter over a pan of simmering water. Once fully melted and combined, remove from heat; whisk in sugar and vanilla. Add in eggs, one at a time, fully incorporating each one before adding the next. 
4. Continue to whisk until mixture is completely smooth and glossy. Add dry ingredients, mix until well combined incorporated. Add in the nuts, if you're adding them.
5. Pour batter into prepared pan.  Bake until a toothpick or cake tester inserted in center comes out with wet crumbs, this will take about 35-45 minutes.  Note: If you wait until toothpick inserted comes out clean, they’re overcooked. You want fudgy crumbs.
6. Cool brownies in pan on a wire rack for five minutes. Cut them up into squares. Can do 16 or 20 squares.