Preheat oven to 180°C.
Line an 8×8-inch (20×20 cm) baking pan with parchment paper, leaving overhang for easy removal.
In a medium bowl, whisk together the melted butter, oil, granulated sugar, and brown sugar until smooth and glossy.
½ cup (113g) unsalted butter, melted, ¼ cup (60ml) neutral oil (vegetable or canola), ½ cup (100g) granulated sugar, ½ cup (100g) dark brown sugar
Add the eggs and vanilla extract. Whisk well for about 30–45 seconds, until slightly thickened.
2 large eggs, 1 tsp vanilla extract
Dissolve the instant coffee powder in 1 tsp hot water. Stir this into the batter.
1 tsp instant coffee powder, 1 tsp hot water
Note: The coffee won’t make the brownies taste like coffee. It simply makes the chocolate flavour deeper and richer.
Sift in the cocoa powder, flour, salt, and baking powder.
½ cup (60g) all-purpose flour, 1/8 tsp salt, ¼ tsp baking powder, ⅓ cup (25g) unsweetened cocoa powder
Gently fold with a spatula just until combined—do not overmix.
Fold in the chocolate pieces or chips.
½ cup (50-80g) chocolate pieces or chips
Pour the batter into the prepared pan and smooth the top evenly.
Bake in the middle rack of the oven for 25 to 28 mins or until a toothpick inserted in the center comes out with a few moist crumbs (not wet batter).
Let brownies cool completely in the pan. This is important for clean heart shapes.
Tip: Chill the brownies for 20–30 minutes before cutting for extra-clean edges.