1. Line an 8-inch square baking pan with parchment paper, leaving an overhang on two sides, and lightly coat it with nonstick spray; preheat the oven to 350°F (175°C).

2. In a medium bowl, stir together 1 3/4 cups graham cracker crumbs, 3/4 cup sweetened shredded coconut, 1/3 cup packed light brown sugar, and 1/4 teaspoon fine sea salt until combined.

3. Pour in 1/2 cup melted unsalted butter and stir until all of the crumbs are evenly moistened, then scoop about 1/2 cup of the mixture onto a small parchment-lined baking sheet for the crumb topping and press the remaining crumbs firmly into the bottom of the prepared pan.

4. Bake both the crust pan and the small tray of crumbs for 10 to 12 minutes, until lightly golden and fragrant, then set them aside to cool; crumble the small tray of crumbs once they are firm.

5. While the crust cools, beat 16 ounces softened cream cheese and 1/2 cup granulated sugar together in a large bowl until smooth and fluffy.

6. Beat in the 2 large eggs one at a time, then mix in 1/3 cup coconut milk or heavy cream and 1 teaspoon vanilla extract just until the filling is smooth and creamy.

7. Pour the cream cheese filling over the baked crust, spread it into an even layer, and bake for 20 to 24 minutes, until the edges are set and the center still has a slight jiggle; cool the pan completely on a rack.

8. For the toffee topping, combine 1 14-ounce can sweetened condensed milk, 1/2 cup packed light brown sugar, 1/4 cup unsalted butter, 2 tablespoons light corn syrup, and 1/4 teaspoon fine sea salt in a medium heavy saucepan over medium-low heat, stirring constantly until smooth and gently bubbling.

9. Continue cooking the mixture for 4 to 6 minutes, stirring, until it thickens slightly and turns a deeper caramel color, then remove from the heat and stir in 1 teaspoon vanilla extract.

10. Pour the warm toffee over the cooled cream layer, spread it quickly to the edges, then immediately sprinkle with the crumbled reserved graham-coconut mixture and 1/4 cup sweetened shredded coconut.

11. Let the bars cool to room temperature, then refrigerate for at least 2 hours, or until fully chilled and set, before lifting from the pan and slicing into 16 squares.