In a small pot, melt the butter on medium heat. Once melted, add the flour and cook, whisking constantly for 1 to 2 minutes, or until golden and fragrant. Gradually whisk in the water and heavy cream. Bring to a simmer and cook, whisking frequently for 1 to 2 minutes, or until thickened. Season with salt and pepper.
Reduce the heat to low. Gradually add the cheese and cook, whisking constantly for 30 seconds to 1 minute, or until smooth. Remove from heat and stir in the hop flowers. Season with salt and pepper to taste.