Preheat the oven to 325 degrees. Then, use a pastry brush to lightly coat the bottom and sides of an 8-inch baking pan. Place parchment paper on the bottom of the pan.
Melt the milk chocolate, semi-sweet chocolate, and butter olive oil over medium-low heat in a small saucepan, stirring continuously until creamy. Set aside.
In a medium bowl, whisk the cocoa powder, flour, and salt.
In a large bowl, whisk the eggs, brown sugar, granulated sugar, and vanilla until combined.
Mix the dry ingredients into the wet ingredients with a rubber spatula until just combined. Then, add the crushed Heath bar and gently mix to incorporate the crushed bits.
Pour the batter into the prepared pan and smooth it out with a spatula. Then, sprinkle it with caramel and Heath chips.
Bake the brownies for 35 to 45 minutes until a toothpick comes out mostly clean with a few crumbs and the top is cracked.
Place the brownie pan on a wire cooling rack and let the brownies cool completely before slicing.
Notes
Storage
Store for up to 5 days at room temperature in an airtight container.
Wrap individual brownies in plastic wrap and freeze them for up to 3 months in an airtight, freezer-safe container or heavy-duty freezer bag.
Bring to room temperature before serving.
Tips
Bring all cold ingredients to room temperature for easier, more complete mixing.
To avoid tough brownies, mix the batter until just combined.
Measure your flour by weight or loosely spoon it into the measuring cup to avoid packing it and using too much.
Use a sharp knife and very gentle, even strokes to slice your brownies to reduce tearing and jagged edges.