Preheat oven to 325 degrees. Spread almonds in a single layer on a baking sheet. Bake for about 12 minutes, until golden and fragrant, stirring halfway through.
Immediately add warm almonds and salt to a high-speed blender or food processor. Let it run for until desired consistency. Stop and scrape down the sides with a spatula every 5 minutes or to incorporate. Add butter to a glass jar with lid and refrigerate.