Creamy Crab Croquettes Japanese-Style

3 Tbsp unsalted butter
1 ¼ cup onion chopped
1 cup button mushrooms chopped
5 Tbsp sifted flour
1/8 tsp cayenne
salt and white pepper to taste
1 cup milk
1 cup crab meat

Coating

1 cup flour
1 egg whisked
1 cup panko breadcrumbs finely crushed (place in zip lock bag and crush with rolling pin)
Frying oil

Melt butter in frying pan on medium heat. Add onions and cook until translucent. Add mushrooms and cook for additional two minutes. Add flour, cayenne, salt, and pepper. Stir to completely coat onions and mushrooms. Add milk and increase heat to bring to a boil. When the mixture has reached a thick consistency add crab and combine. Transfer to a greased ½ sheet pan and spread evenly. Cover with saran wrap. Place in freezer for 15 minutes. Remove and cut into twelve equal pieces. Coat hands with oil and remove one piece at a time and form into patties.

Place flour, egg, and panko in separate bowls. Dip each pattie lightly in flour, dust off any excess. Dip in egg and then panko. 

In large frying pan, heat oil to 350 degrees and fry four patties at a time to avoid oil temperature dropping and not frying properly. Cook until golden brown and place on rack.