Caribbean Plantain Gratin

Name: Caribbean Plantain Gratin
Prep time: 15 min
Cook time: 40 min
Total time: 55 min
Cuisine: Caribbean
Ingredients: 3 large Ripe plantains (or 4 medium ripe plantains) (cut into big chunks); 1 cup Cheddar cheese; 1/2 tsp Salt (plus more for the boiling); 1/4 tsp Black pepper; 2 & 1/2 cups Whole milk (at room temperature); 4 tbsp Butter (at room temperature); 2 tbsp All-purpose flour; 1 tsp Salt; 1/2 tsp Black pepper; 1/8 tsp Fresh or ground nutmeg; 2 sprigs Fresh thyme; 2 Garlic cloves (minced)