Gently melt the dark chocolate using a stovetop or microwave. While it’s still warm, spread the chocolate on the inside and outside of your glass, and drizzle some around the inside rim for an extra indulgent touch.

In a blender, combine the chocolate milk, ice cream, and oat milk. Blend until smooth and creamy.

Slowly pour the blended shake into the prepared glass.

For garnish, shred the blonde or salted caramel chocolate into fine pieces and stick it to the chocolate-lined edges of the glass. Sprinkle in marshmallows and dark chocolate chips for added texture and fun.

Top the shake with whipped cream, if desired, and garnish with the remaining marshmallows, chocolate chips, or a drizzle of chocolate sauce.

Serve immediately with a straw and enjoy this rich and decadent treat!