This study is a piece of practitioner-research that investigates the impact of an intervention that incorporates a process-based view on writing and Self-Regulated Strategies Development. The participants were final-year pupils in a Dutch-medium school in Brussels, Belgium, with a multilingual background. Following the principles of action research, the project has taken a cyclical approach. In a first cycle, the available literature was surveyed to develop a fitting remedial writing programme. This was implemented during an additional weekly remedial lesson over a period of three weeks and consisted of small-group (4 pupils) need-based support and ad hoc modelling of strategic writing behaviour by the tutor. The assignment was a collaboration with the economics teacher, employing writing as a tool to learn. Analysis of the teacher diary and a focus group interview with the tutees found that the intervention lacked sufficient structure and that more explicit attention to metacognition was required. To overcome these shortcomings, in the second cycle, the acrostic OREO was introduced to incorporate explicit verbalisations of strategic behaviour at the level of the paragraph, the text and the writing process. Seven pupils received remediation following the OREO method and engaged in cross-curricular writing for two assignments, each consisting of three weeks of dedicated support for one period a week. A mixed methodology was used to assess the impact of the intervention on learners’ writing proficiency (measured in terms of complexity, accuracy and fluency), self-efficacy and self-regulated strategy use when writing in Dutch. Data were collected via a survey, focus group, keystroke logging, stimulated recall and an interview pre- and post-treatment. No improvement in complexity and accuracy was found but fluency showed a positive trend in all tutees for whom keystroke logging data were available (n: 4). Pupils reported increased self-efficacy in the focus group and an increase in strategy use was observed in the ...