I want to highlight an entire slide in a presentation I am creating in R markdown, much in the same way as was done in this [answer](https://tex.stackexchange.com/a/39074/14826) (without using markdown).

Cannot seem to figure it out though. Below is a dummy example of my failure so far...

```
---
title: "Untitled"
output: beamer_presentation
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = FALSE)
```

## Slide with Bullets

- Bullet 1
- Bullet 2
- Bullet 3

% \setbeamercolor{background canvas}{bg=red}

## Slide with R Output 

\setbeamercolor{background canvas}{bg=red}

```{r cars, echo = TRUE}
summary(cars)
```

```