Preheat the oven to 350 F (180 C) for a conventional oven. If you have a convection oven, lower the temperature by 20 F or 15 C. Position one of the oven rack 3rd from the top and the other one 3rd from the bottom if you are going to bake two trays at the same time. Otherwise, just position one rack in the middle of the oven if you only bake one tray
Line one baking sheet with a parchment paper. If you double the recipe, line two baking sheets or if you have a full-size baking sheet (18 x 26 inches), you only need one
Dissolve instant espresso powder in hot water. Set aside to let it cool down a bit
Whisk all the dry ingredients together to combine
Combine dark brown sugar, sugar, oil, vanilla extract, egg yolk, egg white, and espresso in a bowl using a hand mixer on high speed until light, about 5 minutes . Add the instant espresso and whisk to combine. Sift in the dry ingredient and fold all ingredients together using a sturdy spatula until they are well-combined and you don't see any pockets or dry bits of flour. Fold in the chopped almond and chopped chocolate
The dough is actually going to be a paste-like consistency. Wet and sticky. Use a spatula and scoop half of the dough onto a baking sheet you have lined up with parchment paper. Use a spatula to help you shape it to about 12-14 inches in length and about 2-2 1/2 inches wide. It's not going to be a perfect rectangular, but no worries there
First baking:
Place the baking sheets at the position racks and bake for 20 minutes and rotate the pan halfway through baking, top to bottom, front to back if you bake two trays. The bread should be firm to touch at the end of baking, if not, bake a bit longer
Remove from the oven and let them cool down for 5 minutes. Lower the temperature to 250 F (120 C) for a conventional oven. For a convection oven, lower the temperature by 20 F or 15 C
Slice the bread at a diagonal with a knife into 3/4-inch thick slices. You may roughly get about 9 whole pieces and 2 smaller end pieces
If you prefer a "soft-baked" texture, you can skip the second baking and go straight to "cooling" step
Second baking:
Turn those slices on their sides and bake for another 10-12 minutes. Please note that they do crisp up further as they cool down. So you don't want to bake them too long either
Cooling:
Let the bread cool down completely on a cooling rack and they will crisp up further
Decorate (optional):
Put chocolate chips in a microwave-safe bowl and microwave at a 30 seconds interval until you see there are still few chips that almost melted but not quite. Continue stirring the the chocolate will melt
Drizzle the bread with melted chocolate. Let the chocolate set and then store them in an air-tight container for 2 weeks. They were gone in one day at our house LOL!