Preheat oven to 325 degrees F. Prepare cupcake pan by placing cupcake liners in pan. Set aside.
In a small bowl, whisk together the flour, salt, and baking powder. Set aside.
In a bowl attached to a stand mixer (or with a hand mixer), beat together (with whisk attachment) eggs, sugar, and vanilla on medium-high speed until light and creamy, about 2 minutes (or if you only have paddle attachment, for 5 minutes).
Slowly add in the dry ingredients and mix to just combine, scraping down bowl once in between.
In a saucepan over medium heat (or in a microwave), heat the milk until simmering. Remove from heat and stir in the butter and coconut oil until both are melted.
With mixer on low speed, slowly add the hot milk mixture to the batter, and mix until everything is combined. Scrape down bowl and briefly mix, making sure to not overwork the batter.
Using a large cookie scoop, fill cupcake liners till they are about 2/3 of the way full.
Bake cupcakes on middle rack for 19-22 minutes or until tops spring back when touched. Cool completely on wire rack before icing them.
Icing
In a bowl attached to a stand mixer (or with a hand mixer), beat butter for about 2 minutes until creamy. Add in sugar, cream, and vanilla extract and mix on low speed for 30 seconds then on high speed for 3 minutes. If using unsalted butter, add a pinch of salt to icing to enhance flavor. (I always use salted butter in my icing recipes.)
Pipe icing onto cooled cupcakes and store in airtight container.
