Preparation Whisk sour cream, finely chopped fresh dill, and lemon in small bowl to blend. Season to taste with salt and pepper. DO AHEAD: Dilled cream can be made 8 hours ahead. Chill. Rewhisk before using. Melt butter with olive oil in small skillet over medium-high heat. Add thinly sliced shallot, sprinkle with salt and pepper, and sauté until golden brown, 3 to 4 minutes. Transfer sautéed shallots to paper towels to drain completely (shallot pieces will crisp as they cool). DO AHEAD: Crispy shallots can be made up to 2 hours ahead. Let stand at room temperature. Arrange baguette slices or water crackers on plate. Spread thin layer of dilled cream over each baguette slice or cracker. Carefully arrange salmon slices atop, dividing equally. Spoon small dollop of dilled cream atop each, sprinkle with crispy shallots, and serve.
Preparation Whisk sour cream, finely chopped fresh dill, and lemon in small bowl to blend. Season to taste with salt and pepper. DO AHEAD: Dilled cream can be made 8 hours ahead. Chill. Rewhisk before using. Melt butter with olive oil in small skillet over medium-high heat. Add thinly sliced shallot, sprinkle with salt and pepper, and sauté until golden brown, 3 to 4 minutes. Transfer sautéed shallots to paper towels to drain completely (shallot pieces will crisp as they cool). DO AHEAD: Crispy shallots can be made up to 2 hours ahead. Let stand at room temperature. Arrange baguette slices or water crackers on plate. Spread thin layer of dilled cream over each baguette slice or cracker. Carefully arrange salmon slices atop, dividing equally. Spoon small dollop of dilled cream atop each, sprinkle with crispy shallots, and serve.