1. Preheat oven to 350F:

2. Spray a 9 x 13-inch baking pan with cooking oil then line it with parchment paper.

3. Make the graham cracker crust: Place the graham cracker crumbs and the melted butter in a bowl. Toss with a fork until the crumbs are moist and hold together when squeezed with your hand. Dump the crumbs in the middle of the pan and then press them into an even layer with your fingers or the back of a flat-bottomed cup.

4. Pour the sweetened condensed milk over the graham cracker crust: Spread to the edges of the pan with a spatula.

5. Layer on the rest of the toppings: In this order, sprinkle the chocolate chips, butterscotch chips, pecans, and then sweetened coconut over the top of the condensed milk. Gently press the ingredients down with your palm so they stick to the condensed milk.

6. Bake in the oven for 30 to 35 minutes: Bake until the edges of the bars turn golden-brown and start to pull away slightly from the sides of the pan. Remove from the oven and sprinkle with the sea salt (if using).

7. Cool completely before lifting the bars out of the pan using the parchment paper.