Preheat your oven to 375°F and line two baking sheets with parchment paper.
Cream together the butter and sugar until smooth.
Mix in the peanut butter and eggs, one at a time, ensuring a cohesive blend.
Add baking powder, cinnamon, nutmeg, and buckwheat flour. Stir until well combined.
Fold in oats and raisins (or chocolate chips for a twist).
Form dough into tablespoon-sized balls, flatten slightly, and place on baking sheets.
Bake for 12 minutes, rotating halfway. Allow cookies to cool before transferring to a rack.