1-First Step: Preheat your oven to 350°F. Grease a 9×13-inch baking pan with butter or non-stick spray. Line with parchment for easy removal. This setup prevents sticking and ensures even baking.

2-Second Step: In a large bowl, beat 1 cup softened butter and 1 cup granulated sugar with an electric mixer on medium speed for 2-3 minutes until light and fluffy. Scrape sides often. Add 1 egg, 1 teaspoon vanilla, and ½ cup sour cream. Mix until smooth, about 1 minute. The mixture should look creamy and pale.

3-Third Step: In a separate bowl, whisk 3 cups flour, 1 teaspoon baking soda, and ¼ teaspoon salt. Gradually add dry mix to wet ingredients on low speed. Stir until just combined into a soft dough. Avoid overmixing to keep bars tender.

4-Fourth Step: Transfer dough to prepared pan. Use wet hands or a spatula to spread evenly, about ¼-inch thick. Bake 15-18 minutes. Edges turn light golden, but center stays soft. Do not overbake for that Lofthouse-style pillowy texture. Cool in pan on wire rack for 1 hour, then fully at room temp, 2 hours.

5-Fifth Step: Beat ½ cup softened butter until creamy. Gradually add 3 cups powdered sugar, 2 tablespoons milk, 1 teaspoon vanilla, and food coloring. Mix on medium until fluffy, 2-3 minutes. Adjust milk for spreadable consistency. Taste and add more vanilla if needed.

6-Sixth Step: Spread frosting evenly over cooled bars. Chill in fridge 30 minutes to set. This firms the topping for clean cuts.

7-Final Step: Lift from pan using parchment. Cut into 24 squares or rectangles. Serve at room temp. Pairs well with milk or coffee. Total time: 45 minutes active, plus cooling. Store as noted below. These easy sugar cookie bars recipe yield soft, frosted delights every time.