Food has always played a big part in my life. Growing up, we took great pleasure in eating together as a family. We ate cheap ingredients in season; a meal might have been a globe artichoke with a delicious, nutty, burnt butter and fresh bread for dipping. My mother would eke out leftovers and turn them into something different – and that’s the way I learned to cook.

Food is portrayed in a judgemental way in the media, and some popular diets use expensive ingredients that aren’t kind to the environment. My beautiful grandmother was a model and I remember her, at the age of 85, going on brisk daily walks, but not denying herself butter and cream – she ate proper food, cooked from scratch. I want to feed my children food that I believe is healthy: quality seasonal ingredients and meat that hasn’t been reared with antibiotics. That’s good food.

Food is one of life’s great pleasures; I’m evangelical about how much joy you can have, and give, through cooking. If people are enjoying my food, that makes my recipes successful.

At the end of the day, simply stirring onions in a pan is my way of stepping out of the crazy pace of life. It’s my mindfulness, and the key to my happiness. Organising the kitchen helps me feel calm – I know there’s always sourdough bread and organic milk from the market in the freezer, cheese in the fridge, plus a few chutneys I’ve made at the weekend, and it means I’m relaxed about cooking during the week, as I know I always have ingredients to make a meal fun and delicious.

Home is about warmth, refuge, love and happiness, as well as dealing with the tough things. When we had difficult times growing up, my mother encouraged us to talk – home should be a safe space where you can bring things out in the open.

It’s good that people talk about mental health; my brother is schizophrenic and I had depression in my 20s – if people don’t get support, they fall through [cracks in] the system and become a drain on the economy, plus there are emotional costs. It’s short-sighted that governments don’t invest more in mental health services. I employ 1,300 people – if I’d been allowed to slip through the net, think of that lost taxable income.

Fear of change comes from fear itself, so address fear with reassurance. Life is scary, and if you’re not used to challenging fear, it’s even more so. I couldn’t stick at a job in my 20s; I was desperately trying to find something useful I could do. When I went to Ballymaloe Cookery School, I thought, ‘Thank goodness something feels right at last.’ I believed there was something fundamentally flawed about my character for years; I think a lot of people feel that and it’s such a waste of potential.

I never imagined Wahaca would be the success it is. Ten years ago, we had a vision: to have fun at work and be innovative. We had a shock with the norovirus outbreak [in 2016, Wahaca had to close outlets temporarily], but it was incredible how staff and customers came together. However, it gave us the chance to think about where we were heading, which was valuable.

Email is a negative part of modern life. I tend to catch up with emails in the evenings, but it’s never-ending; if you had to pay 10p every time you emailed, people might think twice. At weekends when I’m with the children, I don’t check my phone.

Injustice makes me angry; if you are an executive and you decide you need a chauffeur, that’s tax-deductible against your income. Yet, if you’re a woman who wants to return to work after having kids, childcare can use up most of your earnings. The loss to the economy of women who can’t afford to work is crazy. Women are expected to do so much… it’s not sustainable. When we are rundown, we carry on because we feel we have to, but we need to stop before we get ill. We all work all the time and I’m not sure it’s healthy. It’s the simple things that make you happy, not the material things.

Home Cook: Over 300 Delicious, Fuss-Free Recipes by Thomasina Miers (Guardian Faber, £25) is out now; thomasinamiers.com

Photograph: Pal Hansen for Psychologies