Mix the egg mixture

• In a bowl, whisk together the eggs, cocoa powder, salt, baking powder, espresso powder and vanilla.

Cream butter and sugar

• In a separate bowl, cream the melted butter with the sugar.
• Microwave in 15-second bursts, stirring between each, until the sugar dissolves and the mixture is shiny.

Combine the mixtures

• Add the egg mixture to the butter mixture and mix well.

Add flour and chocolate chips

• Add the flour and mix gently until just combined, without overmixing.
• Fold in the chocolate chips until evenly distributed.

Bake the brownies

• Pour the batter into a 9x9 pan.
• Bake at 175 °C for 28-30 min, until a toothpick comes out with moist crumbs.

Cool and cut

• Let the brownies cool completely in the pan before cutting into squares.