1-First Step: Preheat your oven to 350°F and grease a 9×13-inch baking pan with butter or non-stick spray. Line with parchment paper for easy removal. This setup ensures even baking and prevents sticking, key for perfect edges on your lofthouse sugar cookie bars.

2-Second Step: In a large bowl, beat 1/2 cup softened butter and 1 cup granulated sugar with an electric mixer on medium speed until light and fluffy, about 2-3 minutes. Scrape down the sides often. Add 1 egg, 1/2 cup sour cream, and 1 tsp vanilla extract. Mix until smooth and creamy. Room-temperature ingredients blend best, avoiding lumps for that soft sugar cookies texture.

3-Third Step: In a separate bowl, whisk together 2 1/2 cups flour, 1/2 tsp baking soda, and 1/4 tsp salt. Gradually add the dry mix to the wet ingredients. Stir on low speed just until combined, about 1 minute. Overmixing toughens the dough, so stop when no flour streaks remain. The batter will be thick and sticky, perfect for bar-style baking.

4-Fourth Step: Transfer the batter to your prepared pan. Use a spatula or wet hands to spread evenly, reaching all corners. Bake for 18-22 minutes. Look for lightly golden edges and a set center; a toothpick should come out clean. Avoid overbaking to keep them soft frosted sugar cookie bars. Cool in the pan on a wire rack for at least 1 hour.

5-Fifth Step: While bars cool, beat 1/2 cup softened butter for frosting until smooth. Gradually add 4 cups powdered sugar, alternating with 2 tbsp milk and 1 tsp vanilla. Mix on medium until fluffy, 2-3 minutes. Add food coloring drop by drop for desired hue. Taste and adjust milk for spreadable consistency.

6-Final Step: Spread frosting evenly over cooled bars. Sprinkle immediately for adhesion. Chill 15 minutes to set, then cut into 24 squares. Serve at room temp for best softness. These best copycat lofthouse sugar cookies pair great with milk or coffee. Total time: 40 minutes active + cooling. Yields soft, addictive treats everyone loves.