Using a food processor crush the garahm crackers along with granulated sugar. You can also put them in a ziplock bag and whack them using your rolling pin.
Transfer crumbs to a bowl and add melted butter to it. Mix till combined and the crumbs feel like wet sand.
Transfer this to your tart pan. I used a 14 x 4.5 inch rectangular tart pan here.
Press the crumbs to form the crust, use the back of your meausuring cup to firmly press the mixture into the pan. Place the tart pan into the refrigerator while you make the filling.
Meanwhile take a bowl and add chocolate chip and 1 tablespoon of unsalted butter to it. Set aside.
Add heavy cream to a pan on medium-low heat. You have to heat the cream till it's warm enough. You don't want to boil it, just when you see small bubbles on the sides, remove it from heat.
Pour this cream over the chocolate chips. Leave the bowl as such for 2-3 minutes.
After 2-3 minutes the chocolate chips would have melted, take a whisk and whisk till you have a smooth ganache. Adding butter is optional but it makes the ganache glossy/shiny.
Once the ganache is smooth, take out your prepared tart pan and pour the ganache on top of the crust. Immediately sprinkle the Valentine's Day M&Ms all over.
Chill the tart in the refrigerator for 4 hours or preferably overnight. Once it's set, cut into pieces and enjoy!