In a medium saucepan, melt butter over medium-high heat. Add milk, sugar, and cocoa and stir to combine while bringing to a boil. Boil for 1-2 minutes, stirring occasionally. Remove pan from heat. Add in peanut butter and vanilla, and stir until smooth. Stir in oats, chopped pretzels, and sea salt.

Drop mixture by spoonfuls onto waxed paper and let cool completely. Cookies will set up and harden when they cool. Store in an air-tight container on the counter for up to 4 days.

Note-you can make these gluten-free by using gluten-free oats and pretzels!