Place the garlic, salt, lemon juice, vegetable oil, and olive oil in a quart-sized jar. Submerge an immersion blender in the mixture to the bottom of the jar. Mix with the blender resting on the bottom of the jar until the ingredients thicken, 1 to 2 minutes. Angle the mixer to pull ingredients from the sides of the jar and lift it toward the top to better combine. Continue blending until the mixture reaches a texture similar to mayonnaise.