1️⃣ Make the Chocolate Cookies

1. Preheat oven to 350°F (175°C) and line two baking sheets with parchment paper.
2. In a large bowl, cream together butter and sugar until smooth (3-4 minutes).
3. Mix in vanilla extract and egg until well combined.
4. In another bowl, whisk together flour, cocoa powder, baking soda, and salt.
5. Gradually add dry ingredients to wet ingredients, mixing until a tacky dough forms.
6. Roll dough into 16 balls (about 1¾ inches in diameter) and place on baking sheets.
7. Bake for 8-10 minutes, until edges are set and centers look slightly glossy.
8. Let cookies cool on baking sheets for 10 minutes, then transfer to a wire rack.

2️⃣ Prepare the Mint Frosting

1. Beat together butter, powdered sugar, milk, mint extract, and green food coloring until creamy.
2. Adjust consistency with more milk (for thinner) or powdered sugar (for thicker).
3. Spread frosting evenly over cooled cookies.
4. Freeze frosted cookies for at least 15 minutes to set.

3️⃣ Make the Chocolate Ganache

1. In a microwave-safe bowl, combine chocolate chips and oil.
2. Microwave in 30-second intervals, stirring after each, until smooth.
3. Spoon melted chocolate over chilled cookies (freezing helps control spread).
4. Let ganache set before serving (about 30 minutes at room temp or 15 minutes in the fridge).