Toss together strawberries, lemon juice and 1/4 cup sugar in a bowl.
Leave to macerate for 1-2 hours.
Crush with fingers or a fork.
In a large mixing bowl with either a whisk or an electric mixer, whip eggs and remaining 3/4 cup sugar until pale and fluffy, about 1 minute.
Whisk in milk, cream and vanilla until fully combined.
Pour base into ice cream maker and churn for 20 minutes.
While still churning, pour in macerated strawberries and churn 5-10 minutes more.
Pour into an airtight container and freeze for at least 4 hours before scooping.
Prepare the meringue.
In a heatproof bowl fitted over a saucepan of simmering water, whisk sugar, egg whites and cream of tartar constantly until dissolved, about 2 minutes.
Remove from heat and whisk with an electric mixer until stiff and glossy, about 10 minutes.
Whisk in vanilla.
To assemble: Place a packed scoop of ice cream (about 3-4 ounces) on brownie base.
Using a spoon or offset spatula, spread meringue all over ice cream and brownie.
Use a swirling motion to create texture.
Toast meringue with a torch and enjoy.