In the bowl of a food processor, grind 2 cups of oats until super fine and flour-like. Add to a large bowl and stir in the remaining 1¾ cups oats and salt. Mix to combine.

Melt the butter, brown sugar, and maple over medium heat in a small saucepan until the butter is completely melted and the sugar is dissolved. Remove from heat and whisk in the almond milk and vanilla extract. Let cool slightly.

Pour the butter mixture into the oat mixture and stir with a wooden spoon until combined. Spoon the mixture into the prepared pan and press the oats into the pan evenly.

Bake until slightly golden brown, rotating halfway through, 20 minutes. Let cool and then slice into bars.