Creamy Lemon Garlic Salmon

Season salmon all over with salt and pepper. In a large skillet over medium-high heat, heat oil. Add salmon, skin side-up, and cook until golden and seared, 6 minutes. Flip and cook until skin is crispy, about 5 minutes. Remove salmon from skillet and transfer to a plate.  Reduce heat to medium, and melt butter. Stir in garlic and cook 30 seconds, then stir in flour and cook 30 seconds more. Whisk in heavy cream. Bring to a simmer and let thicken slightly, 2 to 4 minutes. Stir in lemon zest and juice and dill. Season with salt and pepper then return salmon to skillet and let simmer in sauce for 1 minute. Garnish with crushed red pepper flakes before serving.