Preheat the oven to 350°F.

Line an 8-inch square baking pan with parchment paper. Set aside.

Place the softened butter, brown sugar, and vanilla extract into a large bowl. Use a mixer to cream together the butter and sugar on medium speed for 1 minute, or until pale and fluffy. Add the egg and continue to beat on medium speed until light and fluffy, 30 seconds to 1 minute.

Add the flour, graham cracker crumbs, corn starch, cinnamon, baking powder, and salt to the bowl. Beat the mixture on medium speed for about 1 minute, until all ingredients are combined. Scrape down the sides of the bowl with a rubber spatula as needed.

Transfer the dough to the baking pan. Use a rubber spatula or clean hands to press the dough into an even layer.

Bake the crust on the middle rack of oven until slightly puffy, about 10 minutes.

Remove the baking pan from the oven. Sprinkle the chocolate chips, butterscotch chips, shredded coconut, and chopped pecans evenly over the crust. Drizzle the sweetened condensed milk over the top, allowing it to spread.

Return the pan to the oven and bake until bars are set in the middle and lightly golden brown, 26-30 minutes. If the bars seem to be browning too quickly during cooking, loosely cover them with a sheet of aluminum foil.

Check to see that bars are done. Remove from oven or add time as needed.

Allow bars to cool at room temperature for 15 minutes, then transfer to the refrigerator. Chill for at least 2 hours before slicing.

Lift the bars from the pan by pulling up on the edges of the parchment paper. Slice into squares and serve.