Preheat oven to 350°F. Line two baking sheets with parchment.
Whisk flour, baking powder, baking soda, salt, cinnamon, and nutmeg in a bowl.
Cream butter with brown and granulated sugars until light and fluffy, 2–3 minutes.
Beat in eggs one at a time, then mix in vanilla until smooth.
Add dry ingredients in two additions, alternating with buttermilk. Mix just until combined.
Fold in chopped dates and nuts. Chill dough 10 minutes to firm slightly.
Scoop heaping tablespoons of dough onto sheets, spacing about 2 inches apart.
Bake 10–12 minutes until set at edges and lightly golden on top.
Cool on the sheet 5 minutes, then transfer cookies to a rack to finish cooling.
Notes
Variation: Swap half the nuts for shredded coconut, or add 1 tsp orange zest for a bright citrus note. Storage: Keep in an airtight container at room temperature for 4–5 days, or freeze up to 2 months.This recipe is an original creation inspired by classic German Rock Date Cookies Recipe flavors. All ingredient ratios and instructions are independently developed.