1-First Step: Preheat and Prep the Pan Start by preheating your oven to 350°F (175°C). Lightly grease a 13 x 9 inch baking pan with butter or cooking spray. This prevents sticking and ensures clean slices later. For vegan or low-calorie, use oil spray.

2-Second Step: Mix the Crumb Base In a large bowl, combine 2 1/2 cups of the flour, 1 cup flaked coconut, 1 cup brown sugar, and 1 teaspoon baking soda. Cut in 1/2 cup butter using a pastry blender or two knives until crumbly. This tool gives even crumbs; forks work in a pinch. Gluten-free? Use your blend here. Reserve 1 cup for topping.

3-Third Step: Bake the Crust Press the remaining crumb mixture evenly into the pan bottom. Bake for 10 minutes until lightly golden. This pre-bake sets the base firm. Let it cool slightly while you prep filling; it prevents sogginess from pineapple.

4-Fourth Step: Make the Pineapple Filling In a medium bowl, beat 1/2 cup butter and 1 cup sugar at medium speed until creamy, about 2 minutes. Add 3 eggs one at a time, beating well after each. For vegan, use flax eggs. Gradually beat in the remaining 1 cup flour until smooth, then fold in well-drained crushed pineapple. Low-calorie? Sub yogurt for some butter.

5-Fifth Step: Assemble and Bake Spread the pineapple mixture evenly over the hot crust. Sprinkle reserved crumb mixture on top for that toasted coconut crumble effect. Bake another 25 minutes, or until a wooden pick in the center comes clean. Total bake time keeps them gooey yet set.

6-Final Step: Garnish and Cool While hot, top with toasted flaked coconut for extra crunch and flavor. Cool completely on a wire rack, at least 2 hours, before slicing into squares. This step lets flavors meld and bars hold shape. Store as noted below. Pro tip: chill briefly for cleaner cuts.