Place frozen beans in a large saucepan. Cover the beans with water and add the salt.

Bring beans to a boil then cook for 4-8 minutes, depending on desired doneness.

Drain beans and reserve the water. Wipe saucepan dry with a paper towel. Measure out 1 cup of the reserved water and add the stock cube. Stir so the cube dissolves and set aside.

Melt butter in the same saucepan then add the onion and the thyme-or-summer savory. Saute until the onions are translucent.

Sprinkle the flour on top of the onion mixture and stir till smooth. Let it bubble and cook for 1 minute. Slowly add the cup of reserved water mixture, stirring so there are no lumps. Stir constantly until the liquid thickens; cook for 1 minute.

Add the beans back to the saucepan and simmer for about 2-3 minutes to heat the beans.