Preheat the oven to 325°F. Line a baking sheet with parchment paper or a silicone baking mat.

In a medium bowl, whisk together the all-purpose flour, cocoa powder, baking powder, and salt. Set aside.

In a mixing bowl, cream the butter and sugar together with a paddle attachment. Make sure you scrape the bowl well and beat the mixture until it is light and fluffy.

Add the vanilla extract and the eggs one at a time. Scrape and mix well again.

Slowly add the dry ingredients into the bowl and mix until incorporated. Do not overmix! Then fold in the semi-chocolate chunks.

Divide the biscotti dough in half and place each half onto the lined baking sheet. Using your hands, shape the dough into two logs about 3/4-inch high and 2-inches wide. Spray your hands with vegetable oil to help prevent the dough from sticking to you. Make sure you allow enough space between both logs to spread a few inches wide during the baking process.

Sprinkle a thin layer of sugar on the top of the dough.

Bake the biscotti at 325°F for 45 minutes or until it is completely baked. The biscotti should be firm or bounce back when you press it.

Remove the biscotti from the oven and allow it to cool down. Then turn the oven temperature to 200°F.

Place the biscotti in the fridge for 30 minutes to cool completely and harden. This will make it easier to slice.

Remove the biscotti from the fridge and place it on a cutting board. Slice the biscotti at a diagonal, between 1 – 1 1/4-inches thick. It is normal for the biscotti to crumble when you slice it. You can either keep the rounded ends or begin your diagonal slices by cutting the ends off. If you find it too difficult to slice the biscotti when cold, wait a few minutes for it to come to room temperature and try again.

Place a cooling rack on the baking sheet. Then place the sliced biscotti on the cooling rack. Two cooling racks and baking sheets may be needed. The cooling rack allows for the hot air to circulate evenly around both sides of the biscotti.

Bake the sliced biscotti at 200°F for at least 40 minutes or until they are firm to the touch.

Turn the oven off and remove the biscotti. Let the biscotti cool at room temperature on the cooling rack.

In a double boiler over medium heat, melt the dark or white chocolate. If you want to use both, melt the chocolates in separate bowls. Stir the chocolate constantly until it is smooth and completely melted.

Pour each chocolate in a shallow, rectangular container. Place a parchment sheet of paper next to it.

Carefully, dip the bottom of the biscotti in the melted chocolate. Scrape the bottom using the side of the container to remove any excess chocolate. Place the dipped biscotti on the parchment paper (bottom side down). Repeat this step until all of the biscotti are dipped.Let the chocolate on the biscotti set.

Serve and dunk the biscotti with hot coffee, hot chocolate, or tea.