The intermediate laboratory courses at the Department of Physics, University of Helsinki, were reformed using desired learning outcomes as the basis for design. The reformed laboratory courses consist of weekly workshops and small-group laboratory sessions. Many of the laboratory exercises are open-ended and have several possible ways of execution. They were designed around affordable devices, to allow for the purchase of multiple sets of laboratory equipment. This allowed students to work on the same problems simultaneously. Thus, it was possible to set learning goals which build on each other. Workshop sessions supported the course by letting the students solve problems related to conceptual and technical aspects of each laboratory exercise. The laboratory exercises progressed biweekly to allow for iterative problem solving. Students reached the learning goals well and the reform improved student experiences. Neither positive or negative changes in expert-like attitudes towards experimental physics (measured by E-CLASS questionnaire) were observed.