Preheat the oven to 350ºF (180ºC).
Butter or spray a 9-inch (20x20cm) square baking pan and line it with a strip of parchment paper. See Notes below.
In a large bowl, melt ¾ cup unsalted butter and 6 ounces semisweet chocolate in the microwave or double boiler. See Notes below for methods.
Add 1 cup white sugar and mix for 30 seconds.
Add 1 teaspoon vanilla extract, ½ teaspoon coffee extract or 1 teaspoon instant coffee (dissolved in the vanilla first) and ¼ teaspoon almond extract, if using, and mix well.
Add 3 large eggs and beat by hand until very well mixed.
Add the dry ingredients, sifted (¾ cups all-purpose flour, 1 tablespoon unsweetened cocoa powder and ½ teaspoon salt). Fold well until the batter is shiny and smooth.
Pour the chocolate mixture into the prepared pan and sprinkle with edible Halloween sprinkles.
Bake for 20-25 minutes, until slightly jiggly in the middle.
Remove from the oven and immediately press edible candy eyes on top.
Let cool for 10 minutes and run a smooth-bladed knife along the edges to loosen up any stuck bits.
Let cool completely on a wire rack before removing them. Use the parchment paper to lift the block of brownies. Cut into squares.
You can pop them into the fridge for a few hours to make cutting them easier. They are better the next day, in my opinion, keep for a few days and can be frozen for up to a month, well-wrapped.