Preheat oven to 400°F (200°C). Cut the top off the garlic head, drizzle with olive oil, wrap in foil, and roast for 40 minutes until soft. Squeeze the roasted cloves out and mash into a paste.

In a medium saucepan over medium heat, melt the butter. Add the minced onion and sauté for 5 minutes until soft but not browned.

Stir in the diced ham and cook for another 2 minutes to release its fat.

Add 1/2 cup flour to the pan and stir constantly for 2-3 minutes to cook out the raw flour taste, creating a roux.

Gradually whisk in the warm milk, a little at a time, ensuring the mixture is smooth before adding more. Simmer for 5-8 minutes until the sauce is very thick.

Remove from heat. Stir in the roasted garlic paste, nutmeg, salt, and pepper. Transfer the mixture to a shallow dish, cover with plastic wrap (touching the surface), and refrigerate for at least 2 hours until firm.

Set up a breading station: one bowl with flour, one with beaten eggs, and one with panko breadcrumbs.

Take scoops of the chilled mixture and shape them into small logs or cylinders.

Roll each log in flour, dip in egg, and coat thoroughly in breadcrumbs.

Heat 2 inches of vegetable oil in a deep pan to 350°F (175°C). Fry the croquetas in batches for 2-3 minutes until golden brown and crispy. Drain on paper towels before serving.