Meanwhile, wipe out the pan. Add the remaining 1 tablespoon oil and heat over medium-high heat. Add garlic and cook, stirring, until fragrant, about 30 seconds. Add broth, lemon juice and salt to the pan. Bring to a boil. Whisk half-and-half into the reserved 1 tablespoon flour. Add to the broth mixture and cook, stirring frequently, until reduced by about half and thickened enough to coat the back of a spoon, 8 to 10 minutes. Remove from heat.