01 - 
                Set oven to 175°C (350°F) to ensure even baking temperature.
              
              
              
                02 - 
                Lightly spray a 23x33 cm (9x13 inch) baking pan and line with parchment paper, pressing to fit corners for easy removal.
              
              
              
                03 - 
                Beat softened salted butter with granulated sugar until pale and fluffy, approximately 3 minutes using a mixer.
              
              
              
                04 - 
                Add the egg and vanilla extract to the creamed mixture; beat until smooth and fully combined.
              
              
              
                05 - 
                On low speed, gradually blend in sifted flour and baking powder just until a cohesive dough forms; avoid overmixing to maintain tenderness.
              
              
              
                06 - 
                Distribute dough evenly into prepared pan by spooning and gently pressing to edges, smoothing the surface.
              
              
              
                07 - 
                Bake for 14 to 16 minutes until edges are light golden and center is set but pale. Cool completely on a wire rack.
              
              
              
                08 - 
                Beat softened unsalted butter until creamy. Gradually add sifted powdered sugar, vanilla extract, and cream. Continue beating until fluffy and holding soft peaks, adjusting cream quantity as needed.
              
              
              
                09 - 
                Add gel food coloring dropwise and mix thoroughly until vibrant and uniform orange hue is achieved.
              
              
              
                10 - 
                Spread frosting evenly over cooled bars and garnish with Halloween-themed sprinkles or candy decorations.
              
              
              
                11 - 
                Let frosting set for 10 to 20 minutes. Using a ruler, mark and cut into squares with a clean, warm knife for neat edges.