Creamed Tuna on Toast (Fisherman's SOS)

Why is this one of my favorite dishes? I am not sure, but it felt like childhood right when I started making it. Although I added more tuna than the way my mom used to make it. And onions, and hot sauce, and well...you get the picture.

We always had this during Lent, for sure, and it also spilled its way to the rest of the year because it is simple, classic, comfort food. At Ray's request, I added cheese to the mix, and it is a welcome addition to my basic recipe. It is, however, another entry into the Beige Food Hall of Fame, even with a bit of fresh chive sprinkled on top.
Creamed Tuna on Toast (Fisherman's SOS)
1/2 cup yellow onion, finely diced
5 tablespoons butter
5 tablespoons flour
4 cups whole milk
3 six ounce cans light tuna in water, drained
3-4 drops Tabasco sauce, to taste
1/4 teaspoon nutmeg
1 teaspoon salt
1 teaspoon pepper
4 pieces wheat bread, toasted
4 pieces provolone cheese
Fresh chives, diced, for garnish
In a large sauce pan, melt butter, and saute onions until soft. Add flour, and combine until smooth and golden. Slowly add milk, and stir until smooth. Add tuna, and continue to stir until tuna is broken into smaller pieces. Reduce to simmer, and stir in spices. Simmer, stirring frequently, until sauce thickens, 20-30 minutes. Place one piece of cheese on each piece of toast, and smother with sauce. Top with chives.