True North x Change Makers: Northern Star — Oonagh Simms

Marshmallows usually conjure childhood memories — campfires, hot chocolate, soft sweetness — yet there’s a whole world of flavour and craft hiding behind that simple treat, waiting to be taken seriously.

That shift in perspective is exactly what sparked the journey of Oonagh Simms, Founder of The Marshmallowist, whose approach to confectionery has reimagined what a marshmallow can be. 

What started as a small market stall experiment has grown into a successful confectionery brand with three bakeries and a presence in some of the UK’s most recognisable retailers — all while remaining proudly rooted in Leeds.

Oonagh is one of the inspiring business leaders from True North featured in a special series produced in partnership with the Change Makers podcast. The conversations spotlight Northern Stars who are driving impact in their communities, nurturing future skills and backing bold ideas that make a difference.

She joined the podcast to share how a passion for food became a business, why marshmallows deserve the same respect as fine chocolate and how building a team — including her sister — has helped the company to grow.

From Paris to Portobello Road

I trained as a ​​chocolatier-pâtissier in Paris. Everything in patisserie is about precision and layering flavours. While I was there, I tried a French marshmallow for the first time and it blew my whole concept of marshmallow. They were made from fresh fruit — soft, juicy and completely unlike anything I’d tasted before. It felt like confectionery taken to a much more adult level.

Before that, I’d never really seen confectionery created specifically for adults. If it was aimed at adults, it was usually built around nostalgia — recreating sweets from childhood. That wasn’t something that I wanted to do.

When I came back to the UK, I started selling baked goods from a small market stall on Portobello Road. While at the time it was just a way to make a bit of extra money, that’s where I discovered what I call ‘the magic test’.

When someone tries something that you’ve created and their whole face changes, you know you’re onto something special. We saw that reaction every week. That’s when I realised that marshmallows could become the focus of a business and the magic test worked.

A small stall that snowballed

Things started to move quickly from that point.

One Saturday morning a buyer from Harvey Nichols walked past the stall and showed interest in what we were doing. Soon after, journalists from Vogue approached us and then we were featured in a double-page spread in The Times.

 Then we got a book deal and things snowballed. These tiny little changes created big impacts. However, running the business in London wasn’t sustainable and eventually I realised that we weren’t going to make any money there and the business needed a different environment to grow. 

Moving back to Leeds felt like the right decision. I'm from the region so I wanted to return home and be around a community that would support me.

Family, teamwork & growth

Today, the business is run by my sister Jen and I.

Working with family has been fantastic — she’s my best friend, although it does come with its challenges. Sometimes it can become a bit of an echo chamber where we both agree something is a fantastic idea. We’ve learned to divide responsibilities and Jen focuses more on the day-to-day running of the business while I look after operations.

Building the right team around us has also been essential to growing the company. I was obviously a solo founder before Jen came on board which means that you do everything yourself and become very self-reliant. 

Over time I realised that there are limitations to this. If you want to grow and expand, you need to let other people have a say and trust them to make the best decisions for the company. We’ve been really lucky in that sense. The majority of my team have been with me for seven years, which is very rare in what’s essentially a manufacturing role. 

We approach hiring differently. We don’t hire people just for a specific role — we hire people for their future roles or what they want to achieve within the company.  Jen and I are both mums and 90% of our staff are women, so it was important to us to build a company around flexibility. 

One of the proudest moments recently was seeing someone join us in a temporary packing role and 12 months later she was overseeing an entire production run. It’s magical to see that kind of development in people. 

Scaling with the right support

We hadn’t really gone out looking for investment before. 

We’d been approached by Dragons’ Den and similar sorts of avenues that you’d go down with a company like ours. However, we don’t really like being told what to do and feel a lot of ownership over the company. Marshmallows isn’t the industry I would’ve gone into if I was just trying to make money.

When the Northern Powerhouse Investment Fund came on board, everything changed. They saw our creativity and our potential to scale and there were no strings attached. It allowed us to grow, improve our systems, upgrade packaging and get ready for launching with Marks & Spencer.

It was a real pinnacle moment for the business and our team and it helped us to mature.

Why the North matters

We only started making money when we moved back to Leeds. There’s a capacity to grow here and you can find production units that are affordable for startups. Also, it’s the space — not just for having a production but the space to breathe, go on walks up the moor or be around nature. I feel really strongly about being here.

At the same time, there are still things that could improve when it comes to supporting businesses in the North. Transport infrastructure, for example, plays a big role in people’s ability to work and move around the region.

Most of our team are women which also makes transport really important. I don’t just need a bus to go into the city centre for work — I need a bus to drop my kid off at nursery and go to the shops.

The reality of running a small business

I was very young when I started this company — just 21 — so I’ve grown up with the business and feel like I've learned a lot along the way. There are challenges, for example costs across ingredients and employment expenses have risen. At the same time, it isn’t always possible to pass those increases on to customers.

I don’t want to replace staff with machinery as this is a really skilled role for skilled people. I spend eight hours a day with them and I want to work with a team, not equipment.

Although it’s been tricky, I’d love to still be here in 18 months. If we’re still creating great products and growing, I think that’s a real achievement. 

Reflections for purpose-driven leaders

• Pay attention to the moment when people connect with what you’ve created — that reaction can reveal a real opportunity.
• Build a team that believes in the mission — create opportunities for people to grow within the business.
• Choose partners and investors carefully — growth should never compromise your values.
• Stay resilient through uncertainty — building something creative always comes with challenges.

Shape what’s next for the North

Oonagh is just one of the members of True North who want to build something better — together. 

If you’re committed to supporting the future of the North, join our growing collaborative network of purpose‑driven leaders.