Boil the water first. I put a pot of water on the stove to boil while I start measuring the other ingredients. If you have a hot water faucet, or hot water out of your coffee maker, then that is great as you can just use that. Preheat the oven to 350°F. Line a 9 x 9-inch baking pan with parchment paper.
To make the batter: In a large mixing bowl, add the canola oil, cane sugar, cocoa powder, dark chocolate chips, and heavy whipping cream. Pour the boiling water directly on top of the chocolate chips and mix until combined and the chocolate has completely melted and there are no chunks.
Add in the flour, espresso powder, baking powder, and sea salt in that order. Fold together with a spatula until combined, do not over mix.
Transfer to the prepared baking pan and spread evenly. Bake for 20 to 25 minutes, or until a toothpick inserted in the center comes out clean. Allow to completely in the baking pan.
To make the topping: In a large microwave safe bowl, add the dark chocolate, heavy whipping cream, and butter. Microwave for 30 second intervals, stirring each time in between until the chocolate is melted. This should only take about a 1 minute. Stir to combine completely until you have a smooth ganache.
Pour the ganache over the top of the cooled brownies and spread evenly.
In a microwave safe bowl, melt the white chocolate in 30 second intervals, stirring each time, until melted. Transfer to a piping bag and cut a very small hole.
Pipe horizontal lines of white chocolate, spacing about 1-inch apart. Using a butter knife, draw vertical lines up and down the ganache to create the pattern on the brownies with the white chocolate.
Place in the fridge to set, as it makes the brownies easier to cut when they are chilled. (You could also freeze them for extra clean and perfect cuts). Cut into 16 bars.
Store in the fridge for up to 5 days.