These are my favorites.

Makes about 5 dozen.

1 cup unsalted butter, at room temperature
2 cups sugar
2 large eggs
1 tablespoon vanilla extract
1¾ cups all-purpose flour
1 cup high-quality cocoa powder, such as Droste
1 teaspoon baking soda
½ teaspoon baking powder
½ teaspoon kosher salt
1½ cups toasted walnuts, pecans, or hazelnuts, chopped

1. Preheat the oven to 350 degrees.

2. Place the butter and sugar in a mixer and process until well combined. Add the eggs and vanilla and mix until just combined. Add the remaining ingredients and process until well incorporated.

3. Drop by rounded tablespoons onto a large ungreased baking sheet and bake for about 12 to 13 minutes. Do not overbake. Cool baking sheet between batches.

4. Cool cookies before storing in an airtight container.

From The $50 Dinner Party: 26 Dinner Parties That Won’t Break Your Bank, Your Back, or Your Schedule (Simon & Schuster, 1998)