Set the oven for 190 C / 375 F. Melt your butter over medium heat and set aside to cool for a few minutes.
Meanwhile, bring out a 20 x 30 cm / 8 x 11 '' baking pan (non-stick or other) and grease it with the 1 Tbsp of butter. Pour in the fine bread crumbs and tilt your pan to ensure the bread crumbs cover all sides. Pour out the remaining bread crumbs.
In small bowl, sift together all your dry ingredients except the nuts: flour, cocoa powder, vanilla sugar, baking powder, and fine grain salt. Set aside for now.
In a large bowl, whisk together your eggs and sugar. Mix well, but don't overdo it. You don't want too much air in your batter. Some bubbles on the top of the batter is OK, just not too much.
Add the slightly cooled butter to your egg-and-sugar mixture and mix together. Then add the flour-mixture and mix well.
Mix in the chopped nuts, and then pour the batter into the greased baking pan. Bake in the middle of the oven for about 25 minutes. Test your cake with a toothpick - it's done when the toothpick comes out with just a bit of batter on it.The baking time will differ slightly from oven to oven, so if you're making this for the first time - start with 20 minutes and then leave it for 1-2 more minutes more until your satisfied.
Using unsalted butter? Add some extra salt! A little less than 1/4 tsp should do it.
Baking time will differ with what oven you're using - I've made this in everything from 20 to 35 minutes. If making it for the first time, start out with 20 minutes and if not done, add 1-2 minutes and test again. Repeat until satisfied with the consistency. Test with a toothpick - it's done when it comes out with just a little bit of batter on it.
Choose your nuts based on taste. I love making these brownies with walnuts, but my sister prefers hazelnuts. Those are the only options I've tried but feel free to use your favorite nut. Or make them without nuts - this is delicious as well!