01 -  Preheat the oven to 350°F. Line an 8-inch square baking pan with parchment paper, leaving an overhang for easy removal. 
 02 -  In a medium bowl, whisk together the flour, cocoa powder, cinnamon, baking powder, and salt until well combined. 
 03 -  In a large bowl, whisk the melted butter and granulated sugar until incorporated. Add eggs one at a time, whisking thoroughly after each addition. Stir in the vanilla extract. 
 04 -  Fold the ricotta cheese into the wet mixture until smooth and evenly blended. 
 05 -  Gradually add the dry ingredients to the wet mixture, stirring gently until just combined. Avoid overmixing to retain fudgy texture. 
 06 -  Fold the toasted nuts into the batter. 
 07 -  Pour the batter into the prepared pan and smooth the surface with a spatula. Bake for 32 to 36 minutes, or until a toothpick inserted in the center emerges with a few moist crumbs. 
 08 -  Allow brownies to cool completely in the pan on a wire rack. Use the parchment overhang to lift from the pan, then cut into squares for serving.