Preheat your oven to 300 degrees F and spray 2 mini muffin pans with non-stick spray or line with paper liners. You may also use 1 normal-sized cupcake pan. Set aside.
In a small saucepan, add the beer and bring to a boil over medium-high heat. Reduce the heat and let simmer for 8-10 minutes. Remove from heat and set aside.
Create a double boiler by placing a heat-safe bowl over a simmering pot of water, making sure the bottom of the bowl does not touch the water. To the bowl, add the butter, canola oil, semi-sweet chocolate chips and Nutella. Whisk frequently, until the butter and chocolate have melted and the mixture is smooth. Remove from heat, transfer to a large bowl and set aside to cool for a couple of minutes.
To the large bowl, add the beer, sugars, vanilla extract, sea salt and baking powder. Whisk until smooth. In another bowl, beat the 3 eggs together and then add them to the larger bowl. Whisk again until smooth. Now, fold in the flour until just moistened. Do not overmix.
Pour the brownie batter into your prepared muffin molds. Place in the oven and bake for 30-35 minutes or until a toothpick comes out clean. Remove from heat and set aside to cool completely, about 1 hour.
Once the brownies have cooled slightly, top them with dark chocolate chips, chopped almonds and mini marshmallows. Preheat the broiler and place the brownies in the oven for 1-2 minutes or until the marshmallows have toasted lightly. Keep a close eye. The marshmallows can quickly go from lightly toasted to burnt. Remove from oven and let cool for a couple of minutes before serving.
The brownies will store in an airtight container for 3-4 days. Enjoy!