Prepare the base: In a large bowl, cream together ¾ cup + 2 tbsp softened butter with ¾ cup sugar and 2 tsp vanilla sugar. Beat for 2-3 minutes until the mixture is pale and fluffy. This step incorporates air, which creates the tender crumb in sablé cookies.

Add the eggs: Mix 2 large eggs into the butter and sugar mixture one at a time, beating well after each addition. Make sure each egg is fully incorporated before adding the next. The mixture should be smooth and creamy.

Incorporate dry ingredients: Add 3 ¼ cups all-purpose flour, 1 ½ tsp baking powder, 2 tsp vanilla sugar, and ½ tsp salt to the wet ingredients. Fold gently with a spatula until a cohesive dough forms. Don't overmix—stop as soon as the flour disappears.

Add chocolate and walnuts: Fold 1 ¼ cups chopped dark chocolate and 1 cup chopped toasted walnuts gently into the dough, distributing them evenly throughout.

Shape the cookies: Roll out the dough on parchment paper to about ¼-inch thickness, then cut out your cookies using cookie cutters. Arrange them on a parchment-lined baking sheet with about 1 inch between each cookie.

Bake until golden: Bake in a 302°F (150°C) oven for 25 minutes until the edges are golden brown and the centers are just set. Cool on the baking sheet for 5 minutes before transferring to a cooling rack.